Journal articles on the topic 'SSH SHELL'
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Tohirin, Tohirin. "PENERAPAN KEAMANAN REMOTE SERVER MELALUI SSH DENGAN KOMBINASI KRIPTOGRAFI ASIMETRIS DAN AUTENTIKASI DUA LANGKAH." Jurnal Teknologi Informasi 4, no. 1 (June 2, 2020): 133–38. http://dx.doi.org/10.36294/jurti.v4i1.1262.
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Abstract - System security is an absolute requirement that must be considered by users, especially network administrators to protect data. Every time a system is maintained and monitored, an administrator requires remote access such as a secure shell (SSH) to enter the system with a secure channel. By default, SSH is not secure because there is a great chance that the account will be taken over by brute force techniques. The application of asymmetric cryptography on SSH accounts is considered safe than SSH remote login by default. However, this is still not enough because hackers could control the computer that is used by administrators to do remote servers. It also can be hacked with key scanning techniques. The combination of asymmetric cryptography and two-step authentication can be a solution so that the server will be very difficult to penetrate.Keywords - Server Security, SSH, Asymmetric Cryptosystems, Two-Step Authentication.Abstrak - Keamanan sistem menjadi syarat mutlak yang harus diperhatikan oleh pengguna, khususnya administrator jaringan guna melindungi data. Setiap melakukan pemeliharaan dan monitoring sistem, seorang administrator membutuhkan akses masuk dengan cara remote seperti secure shell (SSH) ke dalam sistem dengan saluran yang aman. Secara default, SSH tidak aman karena berpeluang besar akun diambil alih dengan teknik brute force. Penerapan kriptografi asimetris pada akun SSH dinilai aman daripada remote login SSH secara default. Akan tetapi hal tersebut masih belum cukup karena bisa saja peretas justru mengendalikan komputer yang digunakan oleh administrator dalam melakukan remote server. Selain itu juga dapat diretas dengan teknik key scanning. Kombinasi kriptografi asimetris dan autentikasi dua langkah dapat menjadi solusi sehingga server akan sangat susah ditembus.Kata Kunci – Keamanan Server, SSH, Kriptografi Asimetris, Autentikasi Dua Langkah.
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Hidayat, Muh Adrian Juniarta, and Hadian Mandala Putra. "Sistem Keamanan Server Linux CentOS Dengan Metode Port Knock dan RST Cookies." Infotek : Jurnal Informatika dan Teknologi 6, no. 2 (July 20, 2023): 411–20. http://dx.doi.org/10.29408/jit.v6i2.17500.
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The increase in online-based services makes a security system for server computers increasingly needed. A server computer is a device that must always be available to be accessed anytime and anywhere. Some of the security systems needed for server computers include security for ssh port access for remote server access needs and a security system to protect servers from Denial of Service (DoS) attacks which can make the server down and completely inaccessible. In this study, a security system is proposed for a server computer with the Linux CentOS operating system on a port 22 secure shell(ssh) access system using the port knock method and a security system to prevent Denial of Service (DoS) attacks on server computers using the RST Cookies method. The simulation results from the port 22 Secure Shell (SSH) access experiment for the server computer can work well where port 22 Secure Shell(SSH) will remain closed and cannot be accessed carelessly except by accessing several ports first according to predefined port knocking rules. Likewise, the implementation of a security system with the RST Cookies method works very well to prevent Denial of Service (DoS) attacks and can still keep the server accessible with a good response time of under 1 ms
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Costa, Joana Cabral, Tiago Roxo, Carolina Lopes, João B. F. Sequeiros, Tiago M. C. Simões, and Pedro R. M. Inácio. "Theoretical and practical assessments over SSH." Research and Practice in Technology Enhanced Learning 18 (January 2, 2023): 030. http://dx.doi.org/10.58459/rptel.2023.18030.
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During the COVID-19 pandemic, universities worldwide were forced to close, causing a shift from presential to remote classes. This situation motivated teachers to find suitable tools to evaluate students remotely, fairly, and accurately. However, currently available systems are either survey or exercise evaluation based, not suitable for competency-based assessments. Faced with this context and limitations of available evaluation systems, we developed TestsOverSSH, a system to devise, deliver, and automatically correct assessments performed in a Command Line Interface (CLI) environment. Unique assessments are generated per student when they access the proposed system via Secure SHell (SSH). TestsOverSSH is composed of shell scripts that orchestrate a series of tools and services that come pre-installed in Linux distributions. It can be used to construct multiple-choice or direct answer questions while also requiring students to perform tasks in the environment per se, namely computer programming or CLI manipulation-related assignments. We present examples of the question types in this system, explaining question formats and operating guidelines. Since the assessments are directly performed in the system, logs and command history can be easily retrieved while keeping information within student devices uncollected. We performed evaluations using this system in a real context and obtained student feedback through a custom survey and the System Usability Scale (SUS). Survey results and SUS score suggest that TestsOverSSH is an intuitive evaluation tool, with eased access and usage, making it applicable for e-learning.
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Ramadhan, Rizky, Jonny Latuny, and Samy J. Litiloly. "PERANCANGAN PENGAMANAN SERVER APACHE MENGGUNAKAN FIREWALL IPTABLES DAN FAIL2BAN." Jurnal ISOMETRI 1, no. 1 (May 31, 2022): 9–15. http://dx.doi.org/10.30598/isometri.2022.1.1.9-15.
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Penelitian ini membahas mengenai pemanfaatan firewall dan fail2ban yang dikembangkan menggunakan IpTables guna mengamankan suatu web server dari serangan atau percobaan akses dari pihak-pihak yang tidak berkepentingan. Pemanfaatan firewall dan fail2ban bertujuan agar web server serta aplikasi-aplikasi online yang digunakan aman dari akses pihak-pihak yang tidak berkepentingan serta mencegah pencurian data-data yang sensitive.
Implementasi fail2ban dilakukan dengan fokus kepada mengamankan akses koneksi SSH (secure shell) dimana fail2ban digunakan untuk memblok/memfilter IP Address yang melakukan percobaan koneksi secara beruntun (3x) dan yang masuk ke kriteria serangan.
Hasilnya adalah daftar IP Address yang diblok aksesnya setelah 3x gagal melakukan koneksi ke layanan SSH (secure shell) pada web server dari detail filtering fail2ban diambil sampel IP Address, domain, negara, dan lain-lain yang memberikan indikasi bahwa system firewall yang diterapkan dapat berfungsi dengan benar.
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Desmira, Desmira, and Romi Wiryadinata. "Rancang Bangun Keamanan Port Secure Shell (SSH) Menggunakan Metode Port Knockking." INSANtek 3, no. 1 (May 31, 2022): 1–5. http://dx.doi.org/10.31294/instk.v3i1.552.
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Banten Tour Mandiri merupakan penyedia layanan Tour dan Travel, kebutuhan dalam penggunaan internet pada perusahaan sangat dibutuhkan agar pelayanan dalam bidang jasa dapat terlaksana dengan nyaman dan efektif. Penelitian ini bertujuan 1.Merancang sistem remote menggunakan port knocking untuk memmantau dan mengawasi akses jaringan internet pada PT. Banten Tour Mandiri. 2. Mengawasi jaringan internet pada lingkungan PT. Banten Tour Mandiri. 3.Memudahkan perusahaan dalam mengelola, mengawasi saat menggunakan jaringan internet yang ada di lingkungan perusahaan. Untuk mengembagkan kesetabilan jaringan internet yang ada, namun ada beberapa hal yang belum diperhatikan dan diimplementasikan, yaitu keamanan dan pengawasan terhadap jaringan internet, maka dibutuhkannya suatu sistem keamanan jaringan yang mempermudah pengamanan dan pengawasan, dengan malakukan Rancang Bangun Kemanan Port Secure Shell (SSH) Menggunakan Metode Port Knocking Di PT. Banten Tour Mandiri. Hasil penelitian ini terlihat administrator berhasil melakukan akses remote terhadap server jaringan internet menggunakan port ssh. Pemantauan dan pengelolaan keamanan jaringan internet dapat dilakukan menggunakan PC yang berbeda yang berada pada lingkukan PT. Banten Tour Mandiri
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Desmira, Desmira, and Romi Wiryadinata. "Rancang Bangun Keamanan Port Secure Shell (SSH) Menggunakan Metode Port Knocking." Jurnal Ilmu Komputer dan Sistem Informasi (JIKOMSI) 5, no. 1 (March 3, 2022): 28–33. http://dx.doi.org/10.55338/jikomsi.v5i1.242.
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PT. Banten Tour Mandiri is a tour and travel service provider, the need for internet use in companies is very much needed so that services in the service sector can be carried out comfortably and effectively. This study aims 1. To design a remote system using port knocking to monitor and supervise internet network access at PT. Banten Tour Mandiri. 2. Overseeing the internet network at PT. Banten Tour Mandiri. 3. Make it easier for companies to manage, supervise when using the existing internet network in the corporate environment. To develop the stability of the existing internet network, but there are several things that have not been considered and implemented, namely security and supervision of the internet network, it is necessary to have a network security system that simplifies security and supervision, by performing the Secure Shell (SSH) Port Security Design Port Knocking Method At PT. Banten Tour Mandiri. The results of this study show that the administrator has successfully performed remote access to the internet network server using the SSH port. Monitoring and management of internet network security can be done using a different PC located in the PT. Banten Tour Mandiri
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Zuzcák, Matej, and Petr Bujok. "Using honeynet data and a time series to predict the number of cyber attacks." Computer Science and Information Systems, no. 00 (2021): 40. http://dx.doi.org/10.2298/csis200715040z.
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A large number of cyber attacks are commonly conducted against home computers, mobile devices, as well as servers providing various services. One such prominently attacked service, or a protocol in this case, is the Secure Shell (SSH) used to gain remote access to manage systems. Besides hu man attackers, botnets are a major source of attacks on SSH servers. Tools such as honeypots allow an effective means of recording and analysing such attacks. However, is it also possible to use them to effectively predict these attacks? The prediction of SSH attacks, specifically the prediction of activity on certain subjects, such as autonomous systems, will be beneficial to system administrators, internet service providers, and CSIRT teams. This article presents multiple methods for using a time series, based on real-world data, to predict these attacks. It focuses on the overall prediction of attacks on the honeynet and the prediction of attacks from specific geographical regions. Multiple approaches are used, such as ARIMA, SARIMA, GARCH, and Bootstrapping. The article presents the viability, precision and usefulness of the individual approaches for various areas of IT security.
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Djayali, Abdul Djalil, Rifaldi Nurdin, and Rachmat Saleh Sukur. "IMPLIKASI R-WALL UNTUK PENDETEKSIAN DAN PENGAMANAN SERANGAN SIBER PADA SERVER." Jurnal Komputer dan Informatika 9, no. 1 (March 10, 2021): 45–55. http://dx.doi.org/10.35508/jicon.v9i1.3606.
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Keamanan berbanding terbalik dengan kenyamanan, semakin nyaman dalam penerapan teknologi maka akan berdampak pada sisi keamanan sistem. Server merupakan salah satu infratruktur yang penting dalam mengelolah data. Mencegah serangan pada Server penting untuk dilakukan. Penerapan firewall dapat meminimalisir serangan yang membahayakan Server. Salah satunya dengan menerapkan aplikasi Intrusion Detection System (IDS) seperti Snort yang memiliki kemampuan untuk mendeteksi serangan yang terjadi pada sistem Server. Pada penelitian ini, penulis melakukan pengembangan sistem yang diberi nama R-Wall. Penerapan R-Wall bertujuan untuk mampu memonitor dan mengamankan server terhadap beberapa metode serangan, antara lain yaitu distribution denial of service (DDoS) ping of death, port scanning, brute force pada layanan file transfer protocol (FTP) dan brute force pada layanan secure shell (SSH). Hasil penerapan ini mampu memberikan notifikasi serangan yang dikirimkan melalui robot Telegram dengan total 247 serangan DDoS ping of death, 8 serangan port scanning, 247 serangan brute force pada layanan FTP dan 208 serangan pada layanan brute force SSH. R-Wall juga mampu melakukan pembatasan akses terhadap penyerang.
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Charke, A. Ben, M. Chabi, and M. Fakir. "Contribution to the Security of the Information System." TELKOMNIKA Indonesian Journal of Electrical Engineering 16, no. 1 (October 1, 2015): 154. http://dx.doi.org/10.11591/tijee.v16i1.1599.
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Security of information systems has become a critical problem of companies. In this paper, the principles of security and the description of some attacks that threatening the information system are given. After Techniques of cryptography, digital signature to ensure the confidentiality, integrity and authentication of data, are described. Some security protocol such as Secure Shell (SSH), Secure Socket Layer (SSL), Internet Protocol SECure (IPSEC), in order to ensure the security of connection resources, are described. Intrusion detection is implemented using free IDS "SNORT" software.
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Qiu, Lingling. "Computer-Aided English Teaching Platform Based on Secure Shell Framework." International Journal of Emerging Technologies in Learning (iJET) 14, no. 16 (August 29, 2019): 143. http://dx.doi.org/10.3991/ijet.v14i16.11149.
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With the aid of information-based teaching platform, the traditional classroom English teaching mode can be improved to provide students with a realistic linguistic environment and enhance their learning interest. As a result, the web-based computer aided English teaching has become the mainstream in college English education. Based on the browser/server (B/S) structure, this paper designs a computer-aided English teaching platform of the model–view–controller (MVC) architectural pattern. The programming was carried out using the MySQL database, and the functions of the computer-aided English teaching platform were realized securely and stably by the popular Secure Shell (SSH) framework. The system test results show that the proposed platform supports the open teaching of college English, solves the lack of interaction in traditional classroom teaching, and arouses the students’ learning interest. The research further promotes the reform of college English teaching, and enriches the theories and practices on computer-aided English teaching.
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Triyono, Agus. "IMPLEMENTASI RASPBERRY PI UNTUK APLIKASI SIGNATE BOARD JADWAL KULIAH BERBASIS WEB DENGAN SISTEM OPERASI LINUX." Sebatik 22, no. 2 (December 4, 2018): 102–6. http://dx.doi.org/10.46984/sebatik.v22i2.315.
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Raspberry adalah komputer dengan ukuran fisik yang minimalis dengan kemampuan seperti komputer biasa. Hal ini dapat dimanfaatkan untuk berbagai macam keperluan salah satunya adalah sebagai pemroses penampil jadwal kuliah dengan menggunakan TV layar lebar sebagai media penampil. Sistem terdiri dari dari Raspbery Pi sebagai web hosting, databse server sebagai storage, sebagai router untuk berkomunikasi dengan jaringan TCP/IP dan secure shell servaer sebagai akses untuk proses administrasi atau konfigurasi. Dengan ukuran RAM dan bentuk yang minimal Raspberry Pi dapar menopang operasi-operasi tersebut dengan maksimal. Dengan demikian Raspberry Pi akan diuji kemampuannya jika difungsikan sebagai web server, database server dan SSH server dengan kegunaan sistem informasi jadwal kuliah berbasih web.
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Amien, Januar Al. "IMPLEMENTASI KEAMANAN JARINGAN DENGAN IPTABLES SEBAGAI FIREWALL MENGGUNAKAN METODE PORT KNOCKING." JURNAL FASILKOM 10, no. 2 (August 13, 2020): 159–65. http://dx.doi.org/10.37859/jf.v10i2.2098.
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Abstrak
From the research results is necessary to to protect by closing all the information open ports on a server and give access to ports and services open only to certain users, and to give access in the form of authentication, while not authorized could not access information about the port itself. Then there is one method that can close the Port Knocking all the information about the port using iptables applications and give access rights in the form of a combination of beats that have been determined. the server will overwrite the firewall rules with new rules made under iptables configuration, and immediately open the destination port, and the client access to port of destination. This method has been successful in doing testing and may have been applied to the server by using the operating system Linux Debian 7.3 Wheezy server, the port opened port22 SSH (Secure Shell).
Keywords: Network Security, Port Knocking, Firewall, Iptable, close port, port
Abstract
Dari hasil penelitian Perlu adanya untuk melindungi dengan menutup semua informasi port yang terbuka pada server dan memberikan akses untuk membuka port dan layanan hanya untuk pengguna tertentu, dan memberi akses masuk berupa otentifikasi, sementara yang tidak diberi kewenangan tidak dapat mengakses informasi port itu sendiri. Maka ada satu metode Port Knocking yang bisa menutup semua informasi port dengan menggunakan Aplikasi Iptables dan memberikan hak akses berupa kombinasi ketukan yang sudah di tentukan. server akan meng-overwrite aturan firewall dengan aturan baru yang dibuat berdasarkan konfigurasi IPtables, Dan langsung membuka port tujuan, dan client dapat mengakses port tujuan. Metode ini telah berhasil di lakukan pengujian dan dapat sudah diterapkan pada server dengan menggunkan sistem operasi Debian server Wheezy 7.3 Linux, Dengan port yang di buka port22 SSH(Secure Shell).
Keywords: Network Security, Port Knocking, Firewall, Iptable, port
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Guan, Yunyan, Liangmin Huang, and Maoxian He. "Construction of cDNA subtractive library from pearl oyster (Pinctada fucata Gould) with red color shell by SSH." Chinese Journal of Oceanology and Limnology 29, no. 3 (May 2011): 616–22. http://dx.doi.org/10.1007/s00343-011-0200-x.
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Erdmann, Martin, Benjamin Fischer, Lukas Geiger, Erik Geiser, Dennis Daniel Nick Noll, Yannik Alexander Rath, Marcel Rieger, et al. "Evolution of the VISPA-project." EPJ Web of Conferences 214 (2019): 05021. http://dx.doi.org/10.1051/epjconf/201921405021.
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VISPA (Visual Physics Analysis) is a web-platform that enables users to work on any secure shell (SSH) reachable resource using just their webbrowser. It is used successfully in research and education for HEP data analysis. The emerging JupyterLab is an ideal choice for a comprehensive, browser-based, and extensible work environment and we seek to unify it with the efforts of the VISPA-project. The primary objective is to provide the user with the freedom to access any external resources at their disposal, while maintaining a smooth integration of preconfigured ones including their access permissions. Additionally, specialized HEP tools, such as native format data browsers (ROOT, PXL), are being migrated from VISPA- to JupyterLab-extensions as well. We present these concepts and their implementation progress.
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Jalil, Abdul. "Sistem Kendali Perangkat Elektronik Jarak Jauh Berbasis Jaringan Nirkabel Menggunakan Secure Shell (SSH) dan robot Operating System (ROS)." Jurnal Teknologi Informasi dan Ilmu Komputer 7, no. 6 (December 2, 2020): 1205. http://dx.doi.org/10.25126/jtiik.2020722737.
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<p>Salah satu tantangan di era revolusi industri 4.0 adalah pengembangan sistem kontrol secara jarak jauh menggunakan koneksi jaringan nirkabel. Tujuan penelitian ini adalah membangun sistem kontrol perangkat elektronik jarak jauh dengan memanfaatkan jaringan <em>wireless tethering </em>pada <em>smartphone</em> menggunakan topologi <em>Wireless Local Area Network</em> (WLAN) dan <em>Robot Operating System</em> (ROS) sebagai perangkat lunak kontrol. Pemanfaatan <em>wireless tethering smartphone</em> untuk berbagi koneksi internet dapat dimanfaatkan untuk mengontrol perangkat elektronik yang terkoneksi ke Raspberry Pi. Koneksi jaringan <em>wireless tethering</em> memiliki arsitektur jaringan yang cukup sederhana jika dibandingkan dengan arsitektur pengontrolan jarak jauh lainnya, serta memiliki jarak jangkau koneksi yang cukup jauh dibandingkan dengan koneksi Bluetooth. Metodologi yang digunakan untuk mengontrol perangkat elektronik pada penelitian ini adalah menggunakan <em>Remote Access Control</em> (RAC) berbasis protokol SSH. Pemanfaatan <em>wireless tethering</em> dan aplikasi <em>mobile</em> SSH dapat digunakan untuk mengirim perintah ROS <em>message</em> dari <em>smartphone</em> ke Raspberry Pi untuk mengontrol pin GPIO Raspberry Pi agar aktif <em>high</em> atau aktif <em>low</em>. Pada saat ROS <em>message</em> mengirim perintah ke GPIO untuk aktif <em>high</em>, maka sistem akan memberikan instruksi kepada relay untuk menyalakan perangkat elektronik. Selanjutnya pada saat GPIO menerima perintah untuk aktif <em>low</em>, maka sistem akan memberikan instruksi kepada relay untuk mematikan perangkat elektronik. Hasil penelitian ini adalah <em>smartphone </em>android dapat digunakan untuk mengontrol perangkat elektronik seperti lampu, kipas angin, pemanas ruangan, dan <em>air conditioner</em> secara jarak jauh menggunakan jaringan WLAN berdasarkan perintah dari ROS <em>message</em>. Perangkat elektronik pada penelitian ini dapat di kontrol secara efektif pada jarak 20 meter di dalam ruangan dan 40 meter di area bebas hambatan.</p><p> </p><p class="Judul2"><strong><em>Abstract</em></strong></p><p class="Abstract"><em>One of the challenges in the Industrial Revolution 4.0 is the development of control systems by remotely using a wireless network connection. This study aims to build a control system for controlling the electronic devices by remotely with the utilization of wireless tethering network in the smartphone used Wireless Local Area Network (WLAN) topology and Robot Operating System (ROS) as software for the controller. Utilization of wireless tethering in the smartphone for share the internet connection can be used for control the electronic devices that connected to the Raspberry Pi. The connection of wireless tethering has a simple architecture when compared with the other architecture of the control system by remotely, it then has a long-range connection when compared to the Bluetooth connection. The methodology has used to manage the electronic devices in this study is used Remote Access Control (RAC) based on SSH protocol. The utilization of wireless tethering and mobile SSH can be used to sends ROS message command from smartphone to the Raspberry Pi to control the Raspberry Pi GPIO pin to active high or active low. When android smartphone send ROS message command to the Raspberry Pi to make the GPIO to active high, the system will instruct the relay to turn on the electronic devices. Then when GPIO accepts the instruction to active low, the system will instruct the relay to turn off the electronic devices. The result of this study is that android smartphone can be used to control the electronic devices such as a lamp, fan, heater, and air conditioner by remotely used WLAN network and command from ROS message. The electronic devices on this study can be controlled by effectively with the distance of 20 meters in the rooms and 40 meters at the outside area. </em></p><p class="Judul2"><strong><em><br /></em></strong></p>
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Jamaluddin, Jamaluddin, El Rahmat Jaya Hulu, and Rimbun Siringoringo. "PENGONTROLAN KEAMANAN SISTEM KOMPUTER CLIENT DARI SERANGAN HACKER DAN VIRUS KOMPUTER SECARA JARAK JAUH (REMOTE SERVER) DENGAN MENGGUNAKAN SSH." METHOMIKA Jurnal Manajemen Informatika dan Komputerisasi Akuntansi 7, no. 1 (April 30, 2023): 123–27. http://dx.doi.org/10.46880/jmika.vol7no1.pp123-127.
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Computer system security is very important to be considered by computer users to protect their computers from attacks such as hackers and computer viruses that can take data and damage the user's computer system. Hacker is a person or party who has the skill in breaking through and sneaking to access a computer without the user's permission and can take data and even damage the system on the user's computer. And a Computer Virus is a computer program that copies and inserts copies into the program and can damage the computer system. So that by using SSH (Secure Shell) can control and check computer security from hacker attacks and computer viruses without having to come to the location where there is a client computer or done remotely (Remote Server).
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Pratama, Redo, Mira Orisa, and FX Ariwibisono. "APLIKASI MONITORING DAN CONTROLLING SERVER MENGGUNAKAN PROTOCOL ICMP (INTERNET CONTROL MESSAGE PROTOCOL) DAN SSH (SECURE SHELL) BERBASIS WEBSITE." JATI (Jurnal Mahasiswa Teknik Informatika) 4, no. 1 (September 1, 2020): 397–403. http://dx.doi.org/10.36040/jati.v4i1.2310.
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Sistem monitoring server sangat dibutuhkan bagi seorang administrator. Sebab memastika setiap server dalam kondisi yang baik merupakan tugas utama dari administrator, karena sifat server yang harus dalam kondisi online atau hidup setiap Sistem monitoring yang saat ini digunakan ialah dengan cara mengecek setiap server yang dikelolanya. Dengan cara tersebut maka administrator dapat mengetahui kondisi fisik serta keadaan server dalam keadaan up atau down.
Dengan menggunakan protocoi ICMP (Internet Control Message Protocol) untuk menjalankan fitur monitoring server secara real time, serta menggunakan protocol SSH (Secure Shell) untuk melakukan kontrol server dan juga melakukan transfer file ke server. Dalam Aplikasi monitoring dan kontrol server yang diterapkan dan diuji cobakan dalam sebuah jaringan lokal di Laboratorium Jaringan Komputer Tektnik Informatika S-1 ITN Malang.
Kegiatan monitoring dapat dilakukan melalui aplikasi ini adalah memantau kondisi real time dari server yang dikelola dalam kondisi up atau down serta, apabila server dalam keadaan down maka administrator akan memperoleh sebuah notifikasi. Fitur kontrol server yang dapat dilakukan dalam aplikasi ini ialah mematikan atau menjalankan ulang server, mengolah service yang bejalan diserver, serta fitur untuk melakukan pengiriman file kesebuah server.
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Bucea-Manea-Tonis, Radu, Valentin Kuleto, Šemsudin A. Plojović, Adrian Beteringhe, and Milena P. Ilić. "Securing Big Data for Knowledge Management into a Circular Economy." Sustainability 14, no. 22 (November 10, 2022): 14851. http://dx.doi.org/10.3390/su142214851.
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The main purpose of the article is to find a solution to secure data transfer. Big data, a mark of Industry 4.0, comes with the risk of transferring knowledge. Data management is becoming harder to be administered, and Big Data (BD) can be a good solution for it. Sending data containing information about actions to be taken by the system may expose the values of the system’s parameters. Securing the data will stop any third party from interfering with the communication and sending its commands to the remote system. Thus, the article presents a case study that proves how to secure BD read/write operations using the Gauss function and how to use Secure Shell (SSH), a cryptographic network protocol, to generate key-value pairs for safely operating services over an unsecured network.
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Farid Jatri Abiyyu, Ibnu Ziad, and Ade Silvia Handayani. "Implementasi Compatibility Layer Pada Jaringan Server Diskless Berbasis Lubuntu 18.04 LTS." Elkom : Jurnal Elektronika dan Komputer 13, no. 2 (December 10, 2020): 1–9. http://dx.doi.org/10.51903/elkom.v13i2.207.
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Diskless server is a cluster computer network which uses SSH (Secure Shell) protocol to grant the client an access to the host's directory and modify it's content so that the client don't need a hardisk (Thin Client). One way to design a diskless server is by utilizing "Linux Terminal Server Project", an open source-based script for Linux. However, using Linux has it own drawback, such as it can't cross platform for running an aplication based on Windows system which are commonly used. This drawback can be overcomed by using a compatibility layer that converts a windows-based application's source code. The data which will be monitored is the compatibility layer implementation's result, and the throughput, packet loss, delay, and jitter. The result of measurement from those four parameters resulting in "Excellent" for throughput, "Perfect" for packet loss and delay, and "Good" for jitter.
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Rauf, Abdul, Mahar Faiqurahman, and Denar Regata Akbi. "Secure random port list generator pada mekanisme autentikasi dengan menggunakan Port Knocking dan Secure Socket Layer." Register: Jurnal Ilmiah Teknologi Sistem Informasi 4, no. 2 (July 1, 2018): 103. http://dx.doi.org/10.26594/register.v4i2.1162.
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Port Knocking merupakan proses autentikasi yang dilakukan dengan mengetuk port tertentu untuk membuka dan menutup koneksi menuju suatu service. Pada umumnya, Port Knocking memiliki prosedur penetapan daftar port yang bersifat tetap. Hal inilah yang mendorong munculnya penelitian terkait penerapan Secure Random Port List Generator (SRPLG), melalui perancangan sebuah sistem yang mampu mengacak daftar port yang digunakan untuk knocking. Di samping itu, sistem ini juga didesain agar mampu mengirimkan informasi daftar port teracak tersebut kepada client melalui jalur aman. SRPLG server ini akan di integrasikan pada mekanisme autentikasi Port Knocking. Penerapan metode ini bertujuan untuk menciptakan sebuah prosedur autentikasi yang dinamis, aman dan efisien dalam mengamankan Secure Shell server (SSH server). Hasil pengujian yang didapatkan menunjukkan bahwa SRPLG server dalam mengacak daftar Port Knocking mampu menghasilkan daftar port yang selalu berubah setiap kali ada request dari client. Kemudian dari hasil sniffing yang dilakukan terhadap data yang ditransmisikan oleh SRPLG server dan client menunjukkan bahwa seluruh informasi yang ditangkap telah dienkripsi oleh Secure Socket Layer (SSL). Hasil pengujian peforma SRPLG server terhadap jumlah client yang melakukan request, rata-rata membutuhkan waktu antara 0,01 detik sampai 0,06 detik dalam setiap variasi pengujian peformansi. Pengujian terakhir menunjukkan bahwa SSH server telah berhasil diamankan dengan konfigurasi Port Knocking dari serangan port scanning attack, di mana seluruh informasi port yang ditampilkan, tidak ditemukan satupun celah yang dapat eksploitasi. Port Knocking is an authentication process done by tapping a particular port to open and close the connection to a service. In general, the knocking port has a fixed procedure to assign ports list. This is what prompted the emergence of research related to the implementation of Secure Random Port List Generator (SRPLG), through the design of a system capable of scrambling the list of ports used for knocking. In addition, the system is also designed to be able to transmit random ports list information to clients via a secure path. This SRPLG server will be integrated into the Port Knocking authentication mechanism. Implementation of this method aims to create a dynamic authentication procedure, secure and efficient in securing the SSH server. The test results show that the secure random port list generator server in scrambling the list of knocking ports is able to generate an ever-changing port list every time a client requests. Then from the sniffing done to the data transmitted by the SRPLG server and the client indicates that all captured information has been encrypted by secure socket layer or SSL. Performance test marks SRPLG server to the number of clients who make requests, average takes between 0.01 seconds to 0.06 seconds in every variation of performance testing. In the last test shows SSH server has been successfully secured with Port Knocking configuration from attack port scanning attack, where all port information is displayed, not found any fault that can exploit.
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ElAshry, Abdelrahman F., Mohamed M. Ramadan, Ziad A. ElAlaily, Mahmoud M. Zaied, Catherine M. Elias, Omar M. Shehata, and Elsayed I. Morgan. "Development of a hybrid multi-layer control architecture for a cooperative team of N − homogeneous robots." Transactions of the Institute of Measurement and Control 42, no. 3 (September 27, 2019): 404–21. http://dx.doi.org/10.1177/0142331219872862.
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This paper proposes a hybrid centralized control architecture for formation control of N-homogeneous mobile robots. The addressed problem is maintaining an equilateral triangular formation using three mobile robots while moving towards a desired target avoiding any collision. The proposed architecture is divided into four main subsystems; a main path-planner, a nonlinear Lyapunov-based controller, a Secure Shell (SSH) communication module and an image processing algorithm. The main path-planner subsystem itself is subdivided into three algorithms; brain-like algorithm, sub-path-planner and an information center algorithm. The brain-like algorithm is responsible for all the decision making. On the other hand, the sub-path-planner works on translating the decisions of the brain into more precise decisions to the individual robots. Meanwhile, the information center acts as the memory for the brain to access saved information previously shared between the robots. It is shown that the control algorithm allows any initial allocation of the three robots to converge to a triangle formation in an optimal manner while avoiding collisions. Finally, the potential use of this formation as a platform acting as an autonomous mobile helipad is introduced as a practical application for the proposed architecture.
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Tekle, Kidane M., Sveinung Gundersen, Kjetil Klepper, Lars Ailo Bongo, Inge Alexander Raknes, Xiaxi Li, Wei Zhang, et al. "Norwegian e-Infrastructure for Life Sciences (NeLS)." F1000Research 7 (June 29, 2018): 968. http://dx.doi.org/10.12688/f1000research.15119.1.
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The Norwegian e-Infrastructure for Life Sciences (NeLS) has been developed by ELIXIR Norway to provide its users with a system enabling data storage, sharing, and analysis in a project-oriented fashion. The system is available through easy-to-use web interfaces, including the Galaxy workbench for data analysis and workflow execution. Users confident with a command-line interface and programming may also access it through Secure Shell (SSH) and application programming interfaces (APIs). NeLS has been in production since 2015, with training and support provided by the help desk of ELIXIR Norway. Through collaboration with NorSeq, the national consortium for high-throughput sequencing, an integrated service is offered so that sequencing data generated in a research project is provided to the involved researchers through NeLS. Sensitive data, such as individual genomic sequencing data, are handled using the TSD (Services for Sensitive Data) platform provided by Sigma2 and the University of Oslo. NeLS integrates national e-infrastructure storage and computing resources, and is also integrated with the SEEK platform in order to store large data files produced by experiments described in SEEK. In this article, we outline the architecture of NeLS and discuss possible directions for further development.
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Ferrari, Alessia, Marco D'Oria, Renato Vacondio, Alessandro Dal Palù, Paolo Mignosa, and Maria Giovanna Tanda. "Discharge hydrograph estimation at upstream-ungauged sections by coupling a Bayesian methodology and a 2-D GPU shallow water model." Hydrology and Earth System Sciences 22, no. 10 (October 16, 2018): 5299–316. http://dx.doi.org/10.5194/hess-22-5299-2018.
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Abstract. This paper presents a novel methodology for estimating the unknown discharge hydrograph at the entrance of a river reach when no information is available. The methodology couples an optimization procedure based on the Bayesian geostatistical approach (BGA) with a forward self-developed 2-D hydraulic model. In order to accurately describe the flow propagation in real rivers characterized by large floodable areas, the forward model solves the 2-D shallow water equations (SWEs) by means of a finite volume explicit shock-capturing algorithm. The two-dimensional SWE code exploits the computational power of graphics processing units (GPUs), achieving a ratio of physical to computational time of up to 1000. With the aim of enhancing the computational efficiency of the inverse estimation, the Bayesian technique is parallelized, developing a procedure based on the Secure Shell (SSH) protocol that allows one to take advantage of remote high-performance computing clusters (including those available on the Cloud) equipped with GPUs. The capability of the methodology is assessed by estimating irregular and synthetic inflow hydrographs in real river reaches, also taking into account the presence of downstream corrupted observations. Finally, the procedure is applied to reconstruct a real flood wave in a river reach located in northern Italy.
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Iman Fitri Ismail, Akmal Nizam Mohammed, Bambang Basuno, Siti Aisyah Alimuddin, and Mustafa Alas. "Evaluation of CFD Computing Performance on Multi-Core Processors for Flow Simulations." Journal of Advanced Research in Applied Sciences and Engineering Technology 28, no. 1 (September 11, 2022): 67–80. http://dx.doi.org/10.37934/araset.28.1.6780.
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Previous parallel computing implementations for Computational Fluid Dynamics (CFD) focused extensively on Complex Instruction Set Computer (CISC). Parallel programming was incorporated into the previous generation of the Raspberry Pi Reduced Instruction Set Computer (RISC). However, it yielded poor computing performance due to the processing power limits of the time. This research focuses on utilising two Raspberry Pi 3 B+ with increased processing capability compared to its previous generation to tackle fluid flow problems using numerical analysis and CFD. Parallel computing elements such as Secure Shell (SSH) and the Message Passing Interface (MPI) protocol were implemented for Advanced RISC Machine (ARM) processors. The parallel network was then validated by a processor call attempt and core execution test. Parallelisation of the processors enables the study of fluid flow and computational fluid dynamics (CFD) problems, such as validation of the NACA 0012 airfoil and an additional case of the Laplace equation for computing the temperature distribution via the parallel system. The experimental NACA 0012 data was validated using the parallel system, which can simulate the airfoil's physics. Each core was enabled and tested to determine the system's performance in parallelising the execution of various programming algorithms such as pi calculation. A comparison of the execution time for the NACA 0012 validation case yielded a parallelisation efficiency above 50%. The case studies confirmed the Raspberry Pi 3 B+'s successful parallelisation independent of external software and machines, making it a self-sustaining compact demonstration cluster of parallel computers for CFD.
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Dale, Jim, Richard Wünsch, Jan Palouš, and Ant Whitworth. "The fragmentation of expanding shells – limitations of the thin-shell model." Proceedings of the International Astronomical Union 5, S266 (August 2009): 375. http://dx.doi.org/10.1017/s1743921309991372.
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Mutiara, Dwi Ayu, Khairunnisak Nur Isnaini, and Didit Suhartono. "NETWORK PROGRAMMABILITY FOR NETWORK ISSUE USING PARAMIKO LIBRARY." Jurnal Teknik Informatika (Jutif) 4, no. 4 (August 18, 2023): 751–58. http://dx.doi.org/10.52436/1.jutif.2023.4.4.691.
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In a company, information technology is needed, especially computer networks, to facilitate data communication. The management of a computer network, of course, requires good administration. The criteria for whether or not a network is good can be seen from the performance, reliability, and security indicators so that it will not cause network issues. Events such as server downs, data loss, lost connections, and undetected computers cause the organization's business performance to be disrupted. This study's purpose is to detect network issues with network programmability technology automatically. Paramiko library supports network automation systems and implements OSPF routing protocol in finding the shortest path to send network packets. This study uses the PPDIOO flow, namely prepare, plan, design, implement, operate, and optimize, because it is considered by the flow of making network detection tools. The results showed that the design and implementation of a small-scale network were successfully built by utilizing network programmability technology and the paramiko library, which helps detect network conditions at any time. This design has a dashboard, provisioning, assurance, and policy features that allow administrators to manage and monitor information on each network device. The network design is fitted with REST-API technology and security through a secure shell (ssh) from the Network Controller that can detect the device's connection conditions and the device's health and update the DNS configuration used. Network Issues that have been seen are devices being down, and the connection being lost. Future research can improve features for network troubleshooting when the connection is lost.
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LIU, S. J. "FRACTURE OF THIN PIPES WITH SPH SHELL FORMULATION." International Journal of Computational Methods 08, no. 03 (September 2011): 369–95. http://dx.doi.org/10.1142/s0219876211002691.
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We study the dynamic fracture of thin-walled structure mainly due to impact and explosive loading. Therefore, we make use of a meshless smoothed particle hydrodynamics (SPH) shell formulation based on Mindlin–Reissner's theory. The formulation is an extension of the continuum-corrected and stabilized SPH method, so that thin structure can be modeled using only one particle characterizing mean position of shell surface. Fracture is based on separation of particles. We study tearing of pre-notched plates, fracture due to impact loading and dynamic fracture of cylindrical shells.
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Albar, Muhammad Musa Jusoff, Nurul Ain Jamion, Siti Nor Atika Baharin, Muggundha Raoov, and Kavirajaa Pandian Sambasevam. "Preparation of Novel Commercial Polyaniline Composites for Ammonia Detection." Solid State Phenomena 301 (March 2020): 124–31. http://dx.doi.org/10.4028/www.scientific.net/ssp.301.124.
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Polyaniline (PANI) is one of the unique conducting polymers due to tunable conductivity, acid-base chemistry and optical properties. In this study, commercial PANI was used to prepare PANI/shell composites to enhance the sensitivity of PANI in ammonia (NH3) gas detection. Three types of waste shells were utilized to incorporate into the PANI matrix such as egg shells (ES), crab shells (CS) and mussel shells (MS). The characterizations were done by Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectrophotometer. FTIR spectra confirmed the presence of CaCO3 in the PANI/shell composites’ backbone. Whereas, UV-Vis spectra further confirmed the PANI/shell composites were in the doped state by exhibiting a characteristic peak at ~790-820 nm. Sensor performance of commercial PANI and PANI/shell composite films were studied in terms of sensor measurement and sensor performances (selectivity, reusability and long-term stability). The sensor performances of commercial PANI, PANI/ES and PANI/CS exhibited correlation coefficient of >0.95. In addition, commercial PANI and PANI/CS films exhibited good selectivity for NH3 gas detection in the presence of interfering gases. In conclusion, PANI/shell composites were successfully prepared for NH3 gas detection and PANI/CS exhibited the highest sensitivity compared to other films.
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Dwi Susanto, Ridi Ferdiana, and Selo Sulistyo. "Implementasi Laboratorium Komputer Virtual Berbasis Cloud – Kelas Pemrograman Berorientasi Obyek." Jurnal Nasional Teknik Elektro dan Teknologi Informasi 11, no. 1 (February 23, 2022): 1–7. http://dx.doi.org/10.22146/jnteti.v11i1.3475.
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Pandemi COVID-19 yang terjadi sejak Maret 2020 menyebabkan kegiatan pembelajaran harus dilakukan secara daring. Kegiatan pembelajaran secara daring umumnya dapat dilakukan dengan menggunakan learning management system (LMS) dan aplikasi video conference. Namun, dalam beberapa topik pelajaran dibutuhkan kegiatan praktikum, di antaranya praktikum menggunakan laboratorium komputer. Untuk memenuhi kegiatan praktikum komputer pada masa pandemi, dibutuhkan laboratorium komputer yang dapat diakses secara daring. Salah satu solusi praktikum secara daring adalah laboratorium virtual (Vlab), yaitu laboratorium komputer virtual yang menggunakan teknologi virtualisasi. Vlab menyajikan virtual machine (VM) yang diakses secara daring dengan aplikasi remote access (Remote Desktop Protocol/RDP, Virtual Network Computing/VNC, Secure Shell/SSH). Vlab dapat menggunakan infrastruktur on-premise maupun infrastruktur public cloud. Dibandingkan dengan Vlab berbasis infrastruktur on-premise, Vlab berbasis cloud tidak membutuhkan investasi awal yang mahal dan mengeliminasi perawatan rutin perangkat keras yang kompleks. Makalah ini mengusulkan aplikasi Vlab berbasis cloud dengan Azure Lab Services pada kasus kelas Pemrograman Berorientasi Obyek. Vlab dirancang berdasarkan kebutuhan teknis praktikum pemrograman yang meliputi spesifikasi VM (CPU, RAM, dan penyimpanan), sistem operasi, perangkat lunak yang harus terpasang, hingga jumlah VM dalam satu kelas. Berdasarkan analisis total cost of ownership, biaya penyediaan Vlab berbasis cloud berpotensi lebih murah hingga 26% dibanding Vlab berbasis infrastruktur on-premise. Instalasi Vlab berbasis cloud yang dilakukan menggunakan skrip Powershell dapat diselesaikan dalam enam interaksi dan waktu instalasinya adalah 132 menit. Akses Vlab dapat dilakukan dengan komputer/laptop standar yang memiliki konektivitas internet dan aplikasi klien RDP. Bandwidth yang dibutuhkan untuk mengakses Vlab berbasis cloud berkisar antara 0,13 Mbps hingga 3,09 Mbps. Rentang bandwith tersebut masih berada dalam rentang kecepatan rata-rata jaringan 4G yang tersedia di Indonesia.
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Milyukova, Irina V., and Ruslan D. Yunusov. "Thermostimulation of titanium aluminide synthesis by high-calorie mixtures." Yugra State University Bulletin 15, no. 4 (January 11, 2020): 17–23. http://dx.doi.org/10.17816/byusu2019417-23.
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A comparative microstructural and phase analysis of titanium aluminide samples obtained by SHS method in shells from a highly exothermic thermite mixture and an equimolar mixture of Nickel and aluminum is carried out. The energy of exothermic reactions of the shells allows heating the charge on the basis of titanium and aluminum and starting the SHS reaction in it. In the sinter sample in the Ni-Al shell, the reaction of titanium aluminide synthesis was not complete; the samples have a high-porous structure with small frame inclusions of intermetallides. In the synthesis of samples in the shell of the thermite mixture obtained alloy, optimal porosity and structure. The main phase in the samples obtained in different modes is titanium aluminide, also in both samples there are inclusions enriched in titanium (Ti3Al, Ti2Al phases), while the phase analysis did not reveal the presence of the initial components of the charge.
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Zhang, Zhi-fan, Fu-ren Ming, and A.-man Zhang. "Damage Characteristics of Coated Cylindrical Shells Subjected to Underwater Contact Explosion." Shock and Vibration 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/763607.
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It is of great significance for the protective design of submarine to study the influences of coverings on the damage characteristics of single and double cylindrical shells subjected to underwater contact explosions. The SPH models of single and double cylindrical shells coated with foam silicone rubber are established to analyze shockwave propagation, damage characteristics, and elastoplastic responses, which provides reasonable parameters of covering position and thickness. The results can be concluded as follows: the superposition of multiple waves may cause the inhomogeneity and discontinuity; for the single cylindrical shell with inner or outer coverings, the damage mode is mainly tensile and shear failure is caused by detonation waves and detonation products; compared with out-covering approach, the in-covering approach has better antishock performance; the best protective effect comes out when the thickness of covering is close to that of the shell; as for the double cylindrical shell without interlayer water, the destruction of inner shell mainly results from the puncture of high-speed fragments from the outer shell, so for the outer shell, out-covering is a better choice; however, since the interlayer water is very effective in protecting the inner shell, in-covering will be better for the inner shell.
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Enkhtur, Lkhamsuren, Valentin Silonov, Tsedendorj Gantulga, Galbadrakh Ragchaa, Tsenddavaa Amartaivan, and Khorgolkhuu Odbadrakh. "Static Displacements and Short-Range Order in Ni-14 at. % Ir Alloy." Solid State Phenomena 323 (August 30, 2021): 159–65. http://dx.doi.org/10.4028/www.scientific.net/ssp.323.159.
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In this paper, we are proposing a novel method to estimate static displacements of atoms caused by size effects in fcc substitutional binary polycrystalline solid solutions. Fourier transforms of static displacements of the atoms on every considered shell were calculated using the equations that include dynamical matrix and Fourier transform of interatomic forces. Short-range order parameters on the first seven shells of Ni-14 at. % Ir alloy have been identified from X-ray diffuse scattering intensity by accounting microscopic static displacements of atoms on a particular shell. Pairwise interatomic potentials on the considered shells and critical temperature of disorder-order phase transition were calculated using values of short-range order parameters.
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Huang, Zhenwei, and Xinlu Yu. "Numerical Simulation Study of Expanding Fracture of 45 Steel Cylindrical Shell under Different Detonation Pressure." Materials 15, no. 11 (June 3, 2022): 3980. http://dx.doi.org/10.3390/ma15113980.
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Detonation and fragmentation of ductile cylindrical metal shells is a complicated physical phenomenon of material and structural fracture under a high strain rate and high-speed impact. In this article, the smoothed particle hydrodynamics (SPH) numerical model is adopted to study this problem. The model′s reliability is initially tested by comparing the simulation findings with experimental data, and it shows that different fracture modes of cylindrical shells can be obtained by using the same model with a unified constitutive model and failure parameters. By using this model to analyze the explosive fracture process of the cylindrical shells at various detonation pressures, it shows that when the detonation pressure decreases, the cylindrical metal shell fracture changes from a pure shear to tensile–shear mixed fracture. When the detonation pressure is above 31 GPA, a pure shear fracture appears in the shell during the loading stage of shell expansion, and the crack has an angle of 45° or 135° from the radial direction. When the pressure is reduced to 23 GPA, the fracture mode changes to tension–shear mixing, and the proportion of tensile cracks is about one-sixth of the shell fracture. With the explosion pressure reduced to 13 GPA, the proportion of tensile cracks is increased to about one-half of the shell fracture. Finally, the failure mechanism of the different fracture modes was analyzed under different detonation pressures by studying the stress and strain curves in the shells.
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Auliyah, Riska, Tri Marthy Mulyasari, and Bayu Chondro Purnomo. "KADAR LOGAM BERAT MERKURI (Hg) PADA KERANG HIJAU DI PURWOKERTO KABUPATEN BANYUMAS TAHUN 2018." Buletin Keslingmas 38, no. 2 (June 30, 2019): 199–203. http://dx.doi.org/10.31983/keslingmas.v38i2.4878.
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Along with the increasing of industry in indonesia and the use of various heavy metal materials can have a negative impact one of it is the water pollution by mercury (Hg) heavy metal. Sea water pollution has a very serious impact for the humans, especially who consume sea biota that is come from contaminated waters region. Sea biota that can be used as an indicator of heavy metal pollution is the shellfish. The purpose of this research is to determine the amount of heavy metal mercury (Hg) in the green shells that is sold in Purwokerto Banyumas Regency. The kind of this research is descriptive research. Green shells (pema viriois) samples that are inspected 3 samples. The respondent of this research are green shell seller at Puwokerto Banyumas regency as much as 3 respondents. The Inspection of mercury heavy metal content on green shell using SSA method at The Great Hall of Industry Pollution Prevention Technology (BBTPPI ) Semarang. The Result of merkury (Hg) heavy metals measurement from the green shellfish sample at DK seller 0,022 mg / kg, DKR seller 0,022 mg / kg, and SHS seller 0,021 mg / kg The green shell of DK sample is taken from Alam Indah Beach at Tegal, DKR sample is taken from Kartini sea at Jepara, and SHS sample is taken from Widuri sea Pemalang. The result of respondent knowledge about the danger of mercury (Hg) on the green shell is 28% of Mr A sample respondents, 24% of Mr B respondents and 42% of Mrs C respondents. The researcher concluded that the amount of mercury (Hg) heavy metal on 3 samples of green shell has fulfilled the requirements of the Obal and Food Supervisory Agency of the Indonesian Republic No.HK.00.05.1.52.4011 Year 2009 about the deermination of the maximum contamination limit of microbial and chemical in thr food that is 1.0 Ppm or mg / kg
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Liu, Yonggang, and Robert H. Weisberg. "Ocean Currents and Sea Surface Heights Estimated across the West Florida Shelf." Journal of Physical Oceanography 37, no. 6 (June 1, 2007): 1697–713. http://dx.doi.org/10.1175/jpo3083.1.
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Abstract The across-shelf structures of the ocean circulation and the associated sea surface height (SSH) variability are examined on the west Florida shelf (WFS) for the 3-yr interval from September 1998 to December 2001. Five sets of characteristic circulation patterns are extracted from 2-day, low-pass-filtered data using the self-organizing map: extreme upwelling and downwelling structures with strong currents, asymmetric upwelling and downwelling structures with moderate currents, and a set of transitional structures with weak currents. The temporal variations of these structures are coherent with the local winds on synoptic weather time scales. On seasonal time scales they are related to both the local winds and the water density variations. The circulation is predominantly upwelling during autumn to spring months (October–April) and downwelling during summer months (June–September). Coastal sea level fluctuations are related to both the dynamical responses of the inner shelf circulation to meteorological forcing and the offshore SSH. On long time scales, the offshore SSH variations appear to dominate, whereas on synoptic weather time scales, the inner shelf wind-driven circulation responses are largest. The across-shelf distribution of SSH is estimated from the velocity, hydrography, wind, and coastal sea level data, and the results are compared with satellite altimetry data, thereby providing a means for calibrating satellite altimetry on the shelf.
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Yermolayeva, Yuliya V., Yuriy N. Savin, and Alexander V. Tolmachev. "Controlled Growth of ZnO Nanocrystals on the Surface of SiO2 Spheres." Solid State Phenomena 151 (April 2009): 264–68. http://dx.doi.org/10.4028/www.scientific.net/ssp.151.264.
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The “islands” of ZnO nanocrystals on amorphous monodisperse 200 nm SiO2 spheres (core-shell particles) were obtained by simple one-step technique based on low-temperature crystallization from liquid phase. The influence of starting reagents types and concentration of zinc ions in the reaction mixture on the morphology of ZnO shells obtained was studied. Crystalline structure of ZnO nanocrystals obtained was proofed by the X-ray diffraction data. The average diameter of ZnO nanocrystals on SiO2 spheres is 10 nm according to X-ray diffraction (XRD) and transmission electron microscopy (TEM) data. It was shown that SiO2/ZnO particles obtained have high luminescence characteristics. Photoluminescence spectra of core-shell SiO2/ZnO particles show two emission peaks centred at 386 nm and 570 nm. Core-shell SiO2/ZnO particles obtained are perspective for active photonic crystals creation for UV-spectral region.
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Enkhtor, Lhkamsuren, Ragchaa Galbadrakh, and Valentin Silonov. "Short-Range Order and Static Displacements in Polycrystalline Ni-13.1at. %W Alloy." Solid State Phenomena 271 (January 2018): 98–105. http://dx.doi.org/10.4028/www.scientific.net/ssp.271.98.
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A methodology accounting for the contributions of static displacements of atoms to X-ray diffuse scattering by binary solid solutions with a face-centered cubic lattice was proposed. By microscopic accounting of static displacements of the atoms on the particular shell, we identified short- range order parameters on the first eight shells of Ni-13.1at. %W alloy from the intensity of X-ray diffuse scattering. The Fourier transform of static displacement of the atoms on every considered shell was calculated with the De Launay model using expressions of elements of dynamical matrix and Fourier transforms of quasi elastic forces, which are calculated by the pseudopotential method.
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Mosbeux, Cyrille, Laurie Padman, Emilie Klein, Peter D. Bromirski, and Helen A. Fricker. "Seasonal variability in Antarctic ice shelf velocities forced by sea surface height variations." Cryosphere 17, no. 7 (July 4, 2023): 2585–606. http://dx.doi.org/10.5194/tc-17-2585-2023.
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Abstract. Antarctica's ice shelves resist the flow of grounded ice towards the ocean through “buttressing” arising from their contact with ice rises, rumples, and lateral margins. Ice shelf thinning and retreat reduce buttressing, leading to increased delivery of mass to the ocean that adds to global sea level. Ice shelf response to large annual cycles in atmospheric and oceanic processes provides opportunities to study the dynamics of both ice shelves and the buttressed grounded ice. Here, we explore whether seasonal variability of sea surface height (SSH) can explain observed seasonal variability of ice velocity. We investigate this hypothesis using several time series of ice velocity from the Ross Ice Shelf (RIS), satellite-based estimates of SSH seaward of the RIS front, ocean models of SSH under and near RIS, and a viscous ice sheet model. The observed annual changes in RIS velocity are of the order of 1–10 m a−1 (roughly 1 % of mean flow). The ice sheet model, forced by the observed and modelled range of SSH of about 10 cm, reproduces the observed velocity changes when sufficiently large basal drag changes near the grounding line are parameterised. The model response is dominated by grounding line migration but with a significant contribution from SSH-induced tilt of the ice shelf. We expect that climate-driven changes in the seasonal cycles of winds and upper-ocean summer warming will modify the seasonal response of ice shelves to SSH and that nonlinear responses of the ice sheet will affect the longer trend in ice sheet response and its potential sea-level rise contribution.
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Butkus, R., J. Deikus, Danielius Gužas, and A. Šarlauskas. "The Use of Rigidity Properties in Cylindrical Shells for Noise Reduction." Solid State Phenomena 113 (June 2006): 259–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.113.259.
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The present paper deals with methods aimed at developing calculation models of sound insulation of various cylindrical shells, making it possible to estimate the shell-radiated noise levels. The proposed methodology is based on the mathematical analysis of the cylindrical shell as an element that is subordinated to the equation of dynamic theory of elasticity of thin-walled constructions of variable rigidity. The work provides the corresponding controls of dynamic theory of elasticity in partial derivatives with variable coefficients. Theoretical research and calculations carried out show that sound insulation under analysis at low frequencies is quite high. A slight reduction of sound insulation at high frequencies conditioned by wave processes is also considered.
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Tsimbelman, N. Ya, T. I. Chernova, and T. E. Shalaya. "Engineering Analysis Methods for Hydraulic Shell Structures with Infill." Solid State Phenomena 265 (September 2017): 779–84. http://dx.doi.org/10.4028/www.scientific.net/ssp.265.779.
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The article examines the history of development and state-of-the-art of the design theory of structures of filled shells delivered in “Civil Engineering” specialist, MSc, and postgraduate engineering disciplines courses. The analysis of the engineering design methods based on the theory of shells propositions has been performed. Structural numerical model field of application expansion has been proved. The obtained parameters and proposed methods can be used in numerical simulations using finite element method to analyze and design the thin shell structures with soil infill. The propositions reflecting state-of-the-art of the design theory of the structures under consideration have been set; their place in the logic of delivering engineering disciplines taught to civil engineering students has been designated.
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Ming, F. R., A. M. Zhang, and S. P. Wang. "Smoothed Particle Hydrodynamics for the Linear and Nonlinear Analyses of Elastoplastic Damage and Fracture of Shell." International Journal of Applied Mechanics 07, no. 02 (April 2015): 1550032. http://dx.doi.org/10.1142/s1758825115500325.
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It is a troublesome and focused problem of solid mechanics to solve shell structures with Smoothed particle hydrodynamics (SPH), which is a fully meshfree method. In this paper, an integral model of SPH shell is proposed to more accurately capture the nonlinear strain along the thickness direction. Though the idea is similar to the "Gaussian integral point" in Finite element method (FEM), it is absent and just the first presentation in SPH. Furthermore, focusing on the metal materials, a high-efficiency iteration algorithm for plasticity is derived and the plastic damage theory of Lemaitre–Chaboche is also introduced based on the studies of Caleyron et al. (2011). As for the dynamic fracture of SPH shell, the multiple line segments algorithm is proposed to treat crack adaptively, which overcomes the mesh dependency occurring in mesh method. These algorithms and theories are successfully applied in the integral model of SPH shell of elasticity, plastic damage and dynamic fracture. Finally, the linear and nonlinear analyses of geometry and material are carried out with FEM, the global model and the integral model of SPH shell to prove the feasibility and the accuracy of the integral model.
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Suryadarma, M. W., D. Okgareta, N. H. Latuapo, and A. S. Atmadipoera. "Seasonal variation of some oceanographic parameters in the Arafura Sea – Gulf of Carpentaria." IOP Conference Series: Earth and Environmental Science 1137, no. 1 (January 1, 2023): 012011. http://dx.doi.org/10.1088/1755-1315/1137/1/012011.
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Abstract The shallow continental shelf of Arafura Sea-Gulf of Carpentaria borders the Torres Strait in the east and the deep Banda Sea in the west, where the monsoonal winds system controls shelf circulation. This study aims to investigate spatial and temporal variation of shelf circulation, surface temperature (SST), seas surface height (SSH), using the multi-datasets of validated model output and satellite-derived data. The model reproduced well the satellite derived SST and SSH (corr.> 0.98). The northwesterly monsoonal winds are fully developed between December and February (NWM period), but the southeasterly winds are intensified during the southeast monsoon (SEM). During the monsoon breaks, the southeasterly-easterly winds are still dominant. The shelf circulation is coincident with the wind direction. During the NMW period the eastward flows from Banda basin and Timor Sea are dominant, creating a clockwise circulation within the Gulf. In contrast, the westward flow dominates during the SEM period, creating an anti-clockwise circulation in the Gulf. Exchange of water via the Torres Strait is also seen. Spatial pattern of temperature and SSH reveal a dissimilarity between the Gulf and the Arafura Sea (99.9% of explained variance) with dominant periodicity of annual and semi-annual scales.
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Johnson, James, Franziska Linke, Cathy Merry, and Beth Coyle. "MEDB-24. Tumour secreted extracellular matrix predicts survival and influences migration and cell death in SHH medulloblastoma 3D models." Neuro-Oncology 24, Supplement_1 (June 1, 2022): i110. http://dx.doi.org/10.1093/neuonc/noac079.398.
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Abstract Medulloblastoma is the most common malignant paediatric brain tumour. Four molecular sub-groups exist (WNT, Sonic hedgehog (SHH), Group 3 and Group 4), each associated with different patterns of metastasis and chemoresistance. We have shown that within these sub-groups further clinically relevant sub-types exist, characterised by differential expression of extracellular matrix (ECM) proteins. For example, good overall survival in two-thirds of SHH sub-group patients is associated with the expression of specific ECM proteins. Our aim here is to further characterise these ECM components in SHH medulloblastoma and to determine how they confer better overall survival in this sub-group. Using a combination of 3D OrbiSIMs and immunohistochemical staining we have identified, that when grown in 3D hyaluronic acid hydrogels or as spheroids, SHH medulloblastoma cell lines form an ECM shell-like structure composed of laminin, collagen and lumican. In addition, scRNAseq of SHH hydrogel nodules revealed sub-group specific clusters of cells with high levels of ECM interaction and adhesion. We therefore hypothesise that ECM interaction restricts SHH tumour invasion and metastasis through this shell-like structure. To understand how this ECM shell-like structure potentiates better survival in SHH medulloblastoma we have created a CRISPRcas9 laminin knockout SHH medulloblastoma cell line. 3D culture of the laminin knockout cell line demonstrated that laminin is essential for the formation of 3D cell structures as well as migration in SHH medulloblastoma. Furthermore, we have identified that apoptosis is increased in the laminin knockout SHH cell line, suggesting that apoptosis-targeted therapeutics may represent a beneficial treatment option for SHH patients whose tumours exhibit this ECM shell. In summary, tumour-secreted ECM plays a major role in SHH medulloblastoma progression. Expression of laminin, collagen or lumican can be used to classify SHH patients into low and high-risk groups with different therapeutic outcomes and treatment options.
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Hubber, David A., Sam A. E. G. Falle, and Simon P. Goodwin. "Convergence of SPH and AMR simulations." Proceedings of the International Astronomical Union 6, S270 (May 2010): 429–32. http://dx.doi.org/10.1017/s1743921311000767.
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AbstractWe present the first results of a large suite of convergence tests between Adaptive Mesh Refinement (AMR) Finite Difference Hydrodynamics and Smoothed Particle Hydrodynamics (SPH) simulations of the non-linear thin shell instability and the Kelvin-Helmholtz instability. We find that the two methods converge in the limit of high resolution and accuracy. AMR and SPH simulations of the non-linear thin shell instability converge with each other with standard algorithms and parameters. The Kelvin-Helmholtz instability in SPH requires both an artificial conductivity term and a kernel with larger compact support and more neighbours (e.g. the quintic kernel) in order converge with AMR. For purely hydrodynamical problems, SPH simulations take an order of magnitude longer than the grid code when converged.
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Sehol, Muhamad, Sri Juari Santosa, and Dwi Siswanta. "Imobilisasi Asam Humat Pada Kitin Dan Aplikasinya Sebagai Adsorben Cr(III)." Indo. J. Chem. Res. 5, no. 2 (January 31, 2018): 63–68. http://dx.doi.org/10.30598//ijcr.2018.5-seh.
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Immobilization of humic acid on chitin has been conducted and applied to the adsorption of Cr(III). The humic acid was isolated using NaOH 0.1 M, while chitin was isolated by deproteination of crab shells by using NaOH 3.5 % (w/v) and followed by demineralization using HCl 1 M. Chitin obtained from ambient-temperature-dried crab shell is named as chitin I, and crab shell washed by HOCl solution and followed by drying at ambient temperature is named chitin II. The total acidity of the humic acid was 230.95 cmol/kg, and it was distributed into the acidity of COOH 168.75 cmol/kg, and phenolic-OH 62.20 cmol/kg. Adsorbent A with chitin I as the main material and adsorbent B with chitin II as the main material, resulted the adsorbed humic acid of 9.25 and 1.68% (w/w), respectively. Adsorption of Cr(III) was maximum at pH 5, with rate of constants orde of chitin II>adsorbent B>adsorbent A>chitin I, i.e. 0.3509; ; 0.2488; 0.1553; 0.0568 minute-1, respectively. The capacity of adsorption was in the orde of chitin I>adsorbent B>chitin II>adsorbent A, i.e. 944.77; 912.53; 895.37; 893.81 mg/g, respectively. The energy of adsorption of Cr(III) of chitin II>chitin I>adsorbent A>adsorbent B, i.e. 22.932; 20,945; 20.312; 19.615 kJ/mol, respectively.
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Martí-Henneberg, Jordi. "From State-Building to European Integration: The Role of the Railway Network in the Territorial Integration of Europe, 1850–2020." Social Science History 45, no. 2 (2021): 221–31. http://dx.doi.org/10.1017/ssh.2021.7.
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AbstractThis collection of articles combines a set of works that study the contribution of transport infrastructure to the process of state building in different countries in Western and Central Europe. The focus and the themes treated vary, but have two common denominators: firstly, they are based on either completely original, or previously little-used, primary sources; and secondly, each work reveals new ways of interpreting how transport networks have shaped the territories into which they were introduced. Each article is an example of the wealth of potential approaches available and also helps us to interpret the processes involved in state building, which are a necessary precedent to European Integration (EI). To put the seven works that make up this special issue into context, I shall start this introduction by examining three aspects that complement them. I shall firstly clarify what we mean by EI. Secondly, I shall examine whether EI processes existed prior to the creation of the institutions that were set up after World War II to promote integration. Then, thirdly, and finally, based on the previous analyses, I shall look at the emergence of a railway network in Europe and the role that the European states played in this process. The fourth section will present the articles.
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Kegerreis, J. A., V. R. Eke, P. Gonnet, D. G. Korycansky, R. J. Massey, M. Schaller, and L. F. A. Teodoro. "Planetary giant impacts: convergence of high-resolution simulations using efficient spherical initial conditions and swift." Monthly Notices of the Royal Astronomical Society 487, no. 4 (June 10, 2019): 5029–40. http://dx.doi.org/10.1093/mnras/stz1606.
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ABSTRACT We perform simulations of giant impacts on to the young Uranus using smoothed particle hydrodynamics (SPH) with over 100 million particles. This 100–1000 × improvement in particle number reveals that simulations with below 107 particles fail to converge on even bulk properties such as the post-impact rotation period, or on the detailed erosion of the atmosphere. Higher resolutions appear to determine these large-scale results reliably, but even 108 particles may not be sufficient to study the detailed composition of the debris – finding that almost an order of magnitude more rock is ejected beyond the Roche radius than with 105 particles. We present two software developments that enable this increase in the feasible number of particles. First, we present an algorithm to place any number of particles in a spherical shell such that they all have an SPH density within 1 per cent of the desired value. Particles in model planets built from these nested shells have a root-mean-squared velocity below 1 per cent of the escape speed, which avoids the need for long precursor simulations to produce relaxed initial conditions. Secondly, we develop the hydrodynamics code sph with interdependent fine-grained tasking(swift) for planetary simulations. swift uses task-based parallelism and other modern algorithmic approaches to take full advantage of contemporary supercomputer architectures. Both the particle placement code and swift are publicly released.
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Roskosz, Stanisław. "Porosity in Turbine Blades Cast into New Shell Moulds Made of SiC Based Ceramics." Solid State Phenomena 212 (December 2013): 255–58. http://dx.doi.org/10.4028/www.scientific.net/ssp.212.255.
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The subject matter of the paper is the quantitative evaluation of gaseous and shrinkage porosity in the turbine blades using quantitative metallography methods. The research material consisted of blades with a polycrystalline structure made of IN 713C superalloys. Three different shell mould systems were used during the investment casting: shell A - typical industrial shell mould system and used in this work as the reference; shell B – similar to version A, but SiC grit was applied as back-up stucco; shell C – entirely SiC shell mould system. The blades of superalloy IN-713C cast into the wholly SiC shell mould system have revealed much lower porosity as compared to the blades cast into the typical industrial shell mould system.
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Ming, Fu-Ren, A. Man Zhang, and Xue-Yan Cao. "A robust shell element in meshfree SPH method." Acta Mechanica Sinica 29, no. 2 (March 13, 2013): 241–55. http://dx.doi.org/10.1007/s10409-013-0017-2.
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Gille, Wilfried. "Small-angle scattering analysis of the spherical half-shell." Journal of Applied Crystallography 40, no. 2 (March 12, 2007): 302–4. http://dx.doi.org/10.1107/s0021889806053854.
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For a spherical half-shell (SHS) of diameter D, analytic expressions of the small-angle scattering correlation function \gamma_0(r), the chord length distribution (CLD) and the scattering intensity are analyzed. The spherically averaged pair correlation function p_0(r)\simeq r^2\gamma_0(r) of the SHS is identical to the cap part of the CLD of a solid hemisphere of the same diameter. The surprisingly simple analytic terms in principle allow the determination of the size distribution of an isotropic diluted SHS collection from its scattering intensity.