Journal articles: 'DC Security'

1

Turner, Billy G. "SECURITY: VA to DC." Proceedings of the Water Environment Federation 2006, no. 1 (January 1, 2006): 810–18. http://dx.doi.org/10.2175/193864706783789572.

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Natsios, Deborah. "National Security Sprawl: Washington DC." Architectural Design 75, no. 6 (November 2005): 80–85. http://dx.doi.org/10.1002/ad.179.

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Ansari, Sakil Ahmad, and Jaychand Vishwakarma. "Survey on Database Concurrency Control in Multilevel Secure Database Management Systems." International Journal of Advanced Research in Computer Science and Software Engineering 8, no. 4 (April 30, 2018): 105. http://dx.doi.org/10.23956/ijarcsse.v8i4.645.

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Transactions are vital for database management systems (DBMSs) because they provide transparency to concurrency and failure. Concurrent execution of transactions may lead to contention for access to data, which in a multilevel secure DBMS (MLSIDBMS) may lead to insecurity. In this paper we examine security issues involved in database concurrency control for MLS/DBMSs and show how a scheduler can affect security. We introduce Data Conflict Security; (DC-Security) a property that implies a system is free of convert channels due to contention for access to data. We present a definition of DC Security based on noninterference. Two properties that constitute a necessary condition for DC-Security are introduced along with two other simpler necessary conditions. We have identified a class of schedulers we call Output-State-Equivalent for which another criterion implies DC-Security. The criterion considers separately the behavior of the scheduler in response to those inputs that cause rollback and those that do not. We characterize the security properties of several existing scheduling protocols and find many to be insecure

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Haval, Abhijeet Madhukar. "Integration of Nonlinear Dynamics in Blockchain Security Protocols." Advances in Nonlinear Variational Inequalities 26, no. 2 (June 30, 2023): 94–109. http://dx.doi.org/10.52783/anvi.v26.i2.286.

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Because of its ability to completely revamp current blockchain security methods, this connection is crucial. An effective safeguard against complex assaults, Nonlinear Dynamics (ND) adds a living, breathing component to consensus methods and cryptographic primitives. There is an urgent need for creative, nonlinear methods to strengthen blockchain security in light of present challenges including increasing attack vectors and risks posed by quantum computing. The suggested Dynamic Chaos-based Blockchain Security (DC-BS) system in this paper makes use of the chaotic dynamics present in ND to strengthen various aspects of blockchain security. Adaptive threat detection systems, dynamic consensus methods, and chaos-based encryption are all newly introduced in DC-BS. Validation of DC-BS's efficacy in preventing various attack scenarios through simulation studies demonstrates its advantages in reducing vulnerabilities and responding to new attack types. Various decentralized systems can benefit from DC-BS, including as supply chain management, the Internet of Things (IoT), conventional blockchain networks, and decentralized finance (DeFi). To strengthen the security of various decentralized applications, DC-BS works to increase trust, transparency, and resilience. The effectiveness of DCBS is confirmed by thorough simulation analyses that cover a wide range of attack scenarios, including double-spending assaults, Sybil attacks, and eclipse attacks. Based on the results of the simulations, DCBS is much more effective than conventional blockchain security procedures at reducing these risks. Showcased as well is the technique's capacity to react to changing attack techniques, highlighting its capacity to provide strong security even in dynamic settings.

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Wang, Zhuodi, Kejun Li, Jun Liang, Kaiqi Sun, Jinyu Wang, and Zhijie Liu. "Coordinated Control Strategy of CU-MTDC under Abnormal Conditions Considering Power Supply Security." Applied Sciences 11, no. 4 (February 8, 2021): 1539. http://dx.doi.org/10.3390/app11041539.

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The coastal urban multi-terminal DC (CU-MTDC) is a prospective solution for enhancing the power supply security of the coastal urban power (CUP) grid and integrating the large-scale offshore wind farm. However, the large DC disturbances may significantly impact the CUP power supply security. The existing DC unbalanced power distribution methods are difficult to be applied in the CU-MTDC because of the complicated optimization process and the expansion of the influence range of a DC fault. To solve the above problems, this paper proposes a coordinated control strategy of CU-MTDC under abnormal conditions. First, calculation principles for the active power reference of center coastal urban power (CCUP) grid converters are proposed. Second, a DC unbalanced power coordinated distribution strategy under abnormal conditions is used based on the dynamic priority control to ensure power supply security of the critical AC lines. Third, the controller parameters of CCUP grid converters are calculated. Through a simple control process, the number of the regulation converters is dynamically scheduled according to the DC unbalanced power. The DC fault influence range on the urban power grid can be limited in a sufficiently small area. Simulation verified the effectiveness of the proposed control strategy.

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Ge, Huiyang, Hongbin Sun, and Bin Wang. "Multi-scale AC−DC system voltage security regions." Journal of Engineering 2019, no. 16 (March 1, 2019): 3354–58. http://dx.doi.org/10.1049/joe.2018.8592.

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Drew, Michael E. "Covid-19, Investment Risk, and Retirement Security." Financial Planning Research Journal 6, no. 1 (December 1, 2020): 8–20. http://dx.doi.org/10.2478/fprj-2020-0001.

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ABSTRACT Investment risk and retirement income security are constant bedfellows. This paper provides estimates of investment risk for defined contribution (DC) plan members to illustrate the importance of compounding (both positive and negative) during the accumulation phase of retirement saving and associated retirement income during the decumulation phase. In addition to workers being exposed to investment risk via their DC plan, older workers face significant COVID-19 related headwinds in the labour market. The cresting of investment risk with the current pandemic may create a lost generation of those approaching retirement (and recently retired) through lower contribution rates and an unfavourable path of returns.

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Hussain, Talha, Rizwan Bin Faiz, Mohammad Aljaidi, Adnan Khattak, Ghassan Samara, Ayoub Alsarhan, and Raed Alazaidah. "Maximizing Test Coverage for Security Threats Using Optimal Test Data Generation." Applied Sciences 13, no. 14 (July 16, 2023): 8252. http://dx.doi.org/10.3390/app13148252.

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As time continues to advance, the need for robust security threat mitigation has become increasingly vital in software. It is a constant struggle to maximize test coverage through optimal data generation. We conducted explanatory research to maximize test coverage of security requirements as modeled in the structured misuse case description (SMCD). The acceptance test case is designed through the structured misuse case description for mitigation of security threats. Mal activity is designed from SMCD upon which constraints are specified in object constraint language (OCL) in order to minimize human dependency and improve consistency in the optimal test case design. The study compared two state-of-the-art test coverage maximization approaches through optimal test data generation. It was evident through the results that MC/DC generated optimal test data, i.e., n + 1 test conditions in comparison to the decision coverage approach, i.e., 2n test conditions for security threats. Thus, MC/DC resulted in a significantly lower number of test cases yet maximized test coverage of security threats. We, therefore, conclude that MC/DC maximizes test coverage through optimal test data in comparison to decision coverage at the design level for security threat mitigation.

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Goodman, J., A. P. Dancy, and A. P. Chandrakasan. "An energy/security scalable encryption processor using an embedded variable voltage DC/DC converter." IEEE Journal of Solid-State Circuits 33, no. 11 (1998): 1799–809. http://dx.doi.org/10.1109/4.726580.

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WANG, Lan, Chuanyu WANG, and Juan XUE. "Optimal Investment of Defined Contribution Pension Based on Self-Protection and Minimum Security." Wuhan University Journal of Natural Sciences 28, no. 2 (April 2023): 129–40. http://dx.doi.org/10.1051/wujns/2023282129.

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This paper mainly studies the optimal investment problem of defined contribution (DC) pension under the self-protection and minimum security. First, we apply [see formula in PDF] theorem to obtain the differential equation of the real stock price after discounting inflation. Then, under the constraint of external guarantee of DC pension terminal wealth, self-protection is introduced to study the maximization of the expected utility of terminal wealth at retirement time and any time before retirement. The explicit solution of the optimal investment strategy of DC pension at retirement time and any time before retirement should be derived by martingale method. Finally, the influence of self-protection on the optimal investment strategy of DC pension is numerically analyzed.

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Ibrahim, Ahmad Asrul, Behzad Kazemtabrizi, and Javier Renedo. "Security-Constrained Day-Ahead Operational Planning for Flexible Hybrid AC/DC Distribution Networks." Applied Sciences 9, no. 21 (November 3, 2019): 4685. http://dx.doi.org/10.3390/app9214685.

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A new active network management framework is presented based on a multi-period optimal power flow problem that is bounded by security constraints at the distribution level for upholding the security of supply. This can be achieved through active engagement with flexible demand and distributed generation to prepare for contingency events in day-ahead operational planning. This framework is coupled with a flexible hybrid AC/DC medium voltage (MV) distribution network topology. It contains an integrated multi-terminal medium voltage DC (MVDC) interface for a seamless interaction and integration of the flexible demand and generation on both AC and DC sides of the hybrid network. The active energy management framework when coupled with a flexible hybrid AC/DC topology provides unprecedented degrees of flexibility as well as security of operation under a variety of conditions. To this end, the 75-bus UK generic distribution network has been modified and converted into a hybrid AC/DC network using the integrated MVDC interface. This framework is then deployed to minimise operational costs to the network operator, considering costs of schemes such as distributed generation curtailment and flexible demand shifting, as well as network losses. Results show a significant improvement in operational costs when the network operates as a flexible hybrid when compared to a pure AC or a more conventional AC/DC hybrid.

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Schaus, Stacy, Will Allport, and Justin Blesy. "DC Plans:International Experience and the Need to AddressRetirement Security." Journal of Retirement 2, no. 1 (June 30, 2014): 71–88. http://dx.doi.org/10.3905/jor.2014.2.1.071.

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Ullah, Rahat, Amjad ali, and Shahid Latif. "Security Improvement by using Dual Coded FHSS (DC-FHSS)." International Journal of Computer Applications 76, no. 7 (August 23, 2013): 1–7. http://dx.doi.org/10.5120/13256-0733.

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McLaughlin, John W., Phil Braswell, Muminu Badmus, Carl Banks, and Hiram Tanner. "SECURITY IN OUR NATION's CAPITAL – THE DC WASA PERSPECTIVE." Proceedings of the Water Environment Federation 2007, no. 4 (January 1, 2007): 1–16. http://dx.doi.org/10.2175/193864707787974724.

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Lotfjou, A., M. Shahidehpour, Yong Fu, and Zuyi Li. "Security-Constrained Unit Commitment With AC/DC Transmission Systems." IEEE Transactions on Power Systems 25, no. 1 (February 2010): 531–42. http://dx.doi.org/10.1109/tpwrs.2009.2036486.

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McLaughlin, John W., Phil Braswell, Muminu Badmus, Carl Banks, and Hiram Tanner. "SECURITY IN OUR NATION'S CAPITAL – THE DC WASA PERSPECTIVE." Proceedings of the Water Environment Federation 2007, no. 13 (January 1, 2007): 5509–25. http://dx.doi.org/10.2175/193864707787969126.

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Biskas, P. N., and A. G. Bakirtzis. "Decentralised security constrained DC-OPF of interconnected power systems." IEE Proceedings - Generation, Transmission and Distribution 151, no. 6 (2004): 747. http://dx.doi.org/10.1049/ip-gtd:20041063.

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Zhang, Qiufang, Zheng Shi, Ying Wang, Jinghan He, Yin Xu, and Meng Li. "Security Assessment and Coordinated Emergency Control Strategy for Power Systems with Multi-Infeed HVDCs." Energies 13, no. 12 (June 19, 2020): 3174. http://dx.doi.org/10.3390/en13123174.

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Short-circuit faults in a receiving-end power system can lead to blocking events of the feed-in high-voltage direct-current (HVDC) systems, which may further result in system instability. However, security assessment methods based on the transient stability (TS) simulation can hardly catch the fault propagation phenomena between AC and DC subsystems. Moreover, effective emergency control strategies are needed to prevent such undesired cascading events. This paper focuses on power systems with multi-infeed HVDCs. An on-line security assessment method based on the electromagnetic transient (EMT)-TS hybrid simulation is proposed. DC and AC subsystems are modeled in EMTDC/PSCAD and PSS/E, respectively. In this way, interactions between AC and DC subsystems can be well reflected. Meanwhile, high computational efficiency is maintained for the on-line application. In addition, an emergency control strategy is developed, which coordinates multiple control resources, including HVDCs, pumped storages, and interruptible loads, to maintain the security and stability of the receiving-end system. The effectiveness of the proposed methods is verified by numerical simulations on two actual power systems in China. The simulation results indicate that the EMT-TS hybrid simulation can accurately reflect the fault propagation phenomena between AC and DC subsystems, and the coordinated emergency control strategy can work effectively to maintain the security and stability of systems.

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Nascimento, Igor Ferreira do, and Pedro H. M. Albuquerque. "Fair and balance rate for benefits not scheduled in defined contribution plans." Revista Contabilidade & Finanças 32, no. 87 (December 2021): 560–76. http://dx.doi.org/10.1590/1808-057x202112630.

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ABSTRACT The objective of this study is to propose a methodology that, using multiple decreases, in addition to classified by actuarial profile and source of social security costs, calculates actuarially fair and balanced rates for unscheduled collective costing benefits from Defined Contribution (DC) pension plans. There are no studies in Brazil about costing rates for benefits not scheduled in pension plans of the DC modality. Any institution that pays collective cost social security benefits must determine an actuarial rate that is not insufficient, generating a financial imbalance in the fund, nor excessive, compromising the participant’s income. This work is the first study on costing rates for collective costing benefits from pension plans with DC modalities. Actuarially fair rates are obtained considering multiple decreases and equalizing the present value of contributions and the present value of pension and disability benefits, classified by actuarial profile and source of social security cost. The specific balance rate is determined for each source of social security costs and is obtained considering the actuarially fair rates for each actuarial profile. The general balance rate is obtained by the marginal contribution of each specific balance rate. The proposed methodology was used to calculate the rates of unscheduled benefits with collective costing in DC modality plans. The proposed methodology estimated that the legal changes, resulting from Constitutional Amendment 103/2019, indirectly increased by more than 4% the general balance rate of the unscheduled benefits of the Supplementary Social Security Foundation of the Federal Public Servant of the Executive Branch of the Federal Government (FUNPRESP-Exe).

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Usha, V., N. Rajkumar, Dr M. Shyamala Devi, and C. Saranya Jothi. "GSM based door open and closing system." International Journal of Engineering & Technology 7, no. 2.4 (March 10, 2018): 97. http://dx.doi.org/10.14419/ijet.v7i2.14.11186.

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GSM based Door Access Security System has principle application in security frameworks and it can be utilized as a part of Industries, Shops, Offices and in our homes. It replaces the customary security frameworks which utilizes key to open entryway. This venture has keyless passage to the entryway. Client needs to send secret key through SMS utilizing his/her portable. In the event that the secret key is right then Microcontroller turns on a DC engine and a Relay. Bell is turned on for wrong secret key. In its most straightforward shape Home security is the capacity to control entryway open or close Family security remotely. The transmitter depends on remote GSM strategy the idea Door bolting and opening System utilizes GPRS to open and close the entryway. Not with standing this security will be given utilizing GSM in the event of any unapproved get to. DC engine will then perform activity on entryway either bolting or opening.

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Khalil, Khalid, Sheikh Raheel Manzoor, Muhammad Tahir, Nisar Khan, and Khalid Jamal. "IMPACT OF CYBER SECURITY COST ON THE FINANCIAL PERFORMANCE OF E-BANKING: MEDIATING INFLUENCE OF PRODUCT INNOVATION PERFORMANCE." Humanities & Social Sciences Reviews 9, no. 2 (April 29, 2021): 691–703. http://dx.doi.org/10.18510/hssr.2021.9266.

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Purpose of Study: The study objectives are to: a) conduct a meta-analytical review to analyze the association among cybersecurity costs, such as prevention and detection costs (PDC), response costs (RC), development costs (DC), and indirect costs (IC), on the e-banking product innovation performance (PIP) and financial performance (FP), b) to evaluate the causal association of cyber security costs, i.e., (PDC, RC, DC, and IC) on PIP and FP; and c) investigate the mediating effects of PIP in a relationship between PDC, RC, DC, IC and FP. Methodology: The study sample was the managerial cadre employees of various electronic banks (e-banks) working in Pakistan. The survey was conducted by distributing the questionnaire among the employees of e-banks working in Pakistan. The collected data were estimated via multivariate statistical techniques. Findings: The results of the study showed that a) the costs associated with cybersecurity, specifically PDC, RC, and DC, have a statistically significant effect on PIP and e-banking FP, whereas IC has a negative significant influence on the PIP and FP, b) the PIP has a statistically significant effect on e-banking FP, and c) the PIP partially mediates an association between PDC, RC, DC, and FP, whereas, PIP insignificantly mediates in a relationship amongst IC and e-banking FP. Application of Study: The study will applicable in the modern electronic banking (e-banking) systematic risk control and information security solution. Novelty: The study is novel in the context of cyber security costs, including (PDC, RC, DC, IC) by measuring its influence on PI and e-banking FP.

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Ingram, John, and Polly Ericksen. "Environmental Change, Food Security and Human Health." Epidemiology 20 (November 2009): S257—S258. http://dx.doi.org/10.1097/01.ede.0000362860.41385.dc.

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Paunwala, Mita, and S. Patnaik. "DCT Watermarking Approach for Security Enhancement of Multimodal System." ISRN Signal Processing 2012 (December 18, 2012): 1–11. http://dx.doi.org/10.5402/2012/781940.

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We have addressed a novel watermarking algorithm to support the capacity demanded by the multimodal biometric templates. Proposed technique embeds watermark in low frequency AC coefficients of selected 8 × 8 DCT blocks. Selection of blocks accomplishes perceptual transparency by exploiting the masking effects of human visual system (HVS). Embedding is done by modulating the coefficient magnitude as a function of its estimated value. Neighborhood estimation is used for the weighted DC coefficients from eight neighboring DCT blocks. The weights of the DC coefficients are calculated from local image intrinsic property. For our experimentation we have used iris and finger prints as the two templates which are watermarked into standard test images. The robustness of the proposed algorithm is compared with the few state-of-the-art literature when watermarked image is subjected to common channel attacks.

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Peng, Hanmei, Min Su, Shuaihu Li, and Canbing Li. "Static Security Risk Assessment for Islanded Hybrid AC/DC Microgrid." IEEE Access 7 (2019): 37545–54. http://dx.doi.org/10.1109/access.2019.2899347.

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Shen, Li, Li Jiang, Qing Wang, Yiyu Wen, and Tingjian Liu. "Multi-Period Transmission Expansion Planning for Renewables-Rich Power Grid Enabling Transfer Capacity Enhancement of Hybrid AC/DC Interface." Energies 16, no. 5 (February 23, 2023): 2170. http://dx.doi.org/10.3390/en16052170.

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With the increasing integration of HVDC tie-lines, the regional power systems in both the energy-exporting area and the energy-importing area have been gradually evolving into “strong DC, weak AC” systems. In this paper, a multi-period transmission expansion planning optimization model is proposed for an energy-exporting power grid with hybrid AC/DC interface. While the existing literature has not considered the dynamic security problem in TEP, this paper adopts the conventional total transfer capacity (TTC) index to evaluate the security limit of hybrid AC/DC interface under different transmission expansion schemes. Multiple objectives are considered to reduce the investment cost while promoting the consumption of renewables by enhancing the total transfer capacity of hybrid AC/DC interface. The non-dominated sorting genetic algorithm-II (NSGA-II) is used to compute the optimal solution for the proposed multi-period multi-objective transmission expansion planning problem. A case study on the modified IEEE 39-bus system is presented to demonstrate the effectiveness of the proposed method.

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An, Wenjing, Yuanchao Yang, and Geyi Wu. "Research on optimal power flow of AC/DC hybrid system for civil more electric aircraft." Journal of Physics: Conference Series 2741, no. 1 (April 1, 2024): 012017. http://dx.doi.org/10.1088/1742-6596/2741/1/012017.

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Abstract Modern civil more electric aircraft often use AC/DC systems instead of AC systems to reduce the weight of the power system. Compared with the AC/DC system of the land power grid, the aircraft power system needs to pursue economic operation mode under more complex security constraints. This paper establishes the optimal power flow model of the AC/DC hybrid system of more electric aircraft, which takes minimizing the active power loss of the line as the optimization objective, including the steady-state operation constraints and security constraints of the AC/DC system. The interior point method and prediction correction interior point method are used to solve the model. Then, based on the simplified steady-state model of the B787 power system, the model and algorithm are verified by experiments. The experimental results show that by optimizing the power flow distribution of the power system, the power utilization efficiency of the system has been significantly improved, and its stability and reliability can also be better guaranteed.

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Parah, Shabir A., Javaid A. Sheikh, Nilanjan Dey, and G. M. Bhat. "Realization of a New Robust and Secure Watermarking Technique Using DC Coefficient Modification in Pixel Domain and Chaotic Encryption." Journal of Global Information Management 25, no. 4 (October 2017): 80–102. http://dx.doi.org/10.4018/jgim.2017100106.

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The proliferation of information and communication technology has made exchange of information easier than ever. Security, Duplication and manipulation of information in such a scenario has become a major challenge to the research community round the globe. Digital watermarking has been found to be a potent tool to deal with such issues. A secure and robust image watermarking scheme based on DC coefficient modification in pixel domain and chaotic encryption has been presented in this paper. The cover image has been divided into 8×8 sub-blocks and instead of computing DC coefficient using Discrete Cosine Transform (DCTI, the authors compute DC coefficient of each block in spatial domain. Watermark bits are embedded by modifying DC coefficients of various blocks in spatial domain. The quantum of change to be brought in various pixels of a block for embedding watermark bit depends upon DC coefficient of respective blocks, nature of watermark bit (0 or 1) to be embedded and the adjustment factor. The security of embedded watermark has been taken care of by using chaotic encryption. Experimental investigations show that besides being highly secure the proposed technique is robust to both signal processing and geometric attacks. Further, the proposed scheme is computationally efficient as DC coefficient which holds the watermark information has been computed in pixel domain instead of using DCT on an image block.

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Wang, Bao Hua, and Zhong Ke Shi. "Dynamic Adaptive Sliding Mode DC Power Modulation Controller in Parallel AC/DC Transmission System." Advanced Materials Research 433-440 (January 2012): 6783–88. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.6783.

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The effective DC power modulation controller influences the security and stability of AC/DC interconnected power system significantly. Based on the direct feedback linearization model of parallel AC/DC transmission system, the DC power modulation controller is designed by using the dynamical adaptive sliding mode control designing method. Using an adaptive technique to estimate the switching control gain and damping coefficient, the dynamical sliding surface is proposed to eliminate tremble. The proposed adaptive sliding mode control scheme can be implemented without the requirement that the bounds of the uncertainties and the disturbances should be known in advance; meanwhile its design is very simple. The simulation results show that this proposed controller is superior to the nonlinear H∞ DC power modulation controller in damping oscillation and robustness.

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Goldhaber, Dan, and Cyrus Grout. "Pension Choices and the Savings Patterns of Public School Teachers." Education Finance and Policy 11, no. 4 (October 2016): 449–81. http://dx.doi.org/10.1162/edfp_a_00208.

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This paper examines the savings behavior of public school teachers who are enrolled in a hybrid pension plan that includes a defined contribution (DC) component. Few states have incorporated DC features into teacher pension systems and little is known about how providing teachers with greater control over deferred compensation might affect their savings behavior—an important determinant of retirement security. We find the retirement savings choices of teachers—how much they opt to contribute to a DC retirement account—to be generally consistent with that of their peers in the private sector. In particular, age and salary are positively correlated with contribution rates, and contribution rates increase with teaching experience. Importantly, our analysis of retirement wealth suggests that Washington's hybrid plan is likely to provide a level of retirement security for a typical teacher that is comparable to or greater than that provided by the state's pure defined benefit plan.

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Maier Cocco, Gabriel, Fábio Ecke Bisogno, Robinson Figueiredo de Camargo, Eric Glende, and Martin Wolter. "DC voltage ancillary controller for dynamic security of shunt-compensated microgrids." at - Automatisierungstechnik 71, no. 12 (November 27, 2023): 1040–50. http://dx.doi.org/10.1515/auto-2023-0128.

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Abstract Modern power systems require special features from the distributed energy resources especially to meet the power quality and dynamic security. The distribution static synchronous compensator (DSTATCOM) has a safe DC voltage operating range that is often unexplored. Self-excited induction generators (SEIGs) with a shunt DSTATCOM is a well-known solution for low-power, low-cost generation. These systems may have poor robustness against surges and contingencies. This paper proposes an ancillary controller as a supplement in the shunt compensation of an off-grid distributed generation system powered by SEIGs. The controller consists of a variable structure that uses an adequate DC bus capacitor voltage range to provide fast frequency response (FFR) with soft recovery. The control performance for fault rejection is evaluated as well as for load disturbances and generation contingency. Simulation results are presented to demonstrate system operation and compensator performance.

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Nishanthi B, Dr. Kanakaraj K, and Sinthana S D. "Design of Fuzzy PI Controller for Voltage Regulation in DC Micro-Grid." International Journal of Engineering and Management Research 13, no. 1 (February 28, 2023): 112–19. http://dx.doi.org/10.31033/ijemr.13.1.14.

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Efficiency, standard and security of a micro-grid can be tested by measuring the voltage regulation in the DC bus. Photovoltaic micro-grid are prone to time invariant and non-linearity due to variation in solar irradiance. Energy storage device is incorporated to overcome such variations. Traditionally using PI controllers, we can control the charging and dis-charging of battery which only regulates voltage in the bus but it fails to control the fluctuations in the DC bus. Therefore, Fuzzy PI controller is proposed in this paper where it employs the intelligent controlling method thereby reducing the fluctuations in the DC bus. Keywords—Fuzzy, PI, Fuzzy-PI, DC-micro-grid, closed loop control, voltage regulation.

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Wu, Xiong, Zhao Wang, Tao Ding, and Zhiyi Li. "Hybrid AC/DC Microgrid Planning with Optimal Placement of DC Feeders." Energies 12, no. 9 (May 9, 2019): 1751. http://dx.doi.org/10.3390/en12091751.

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With the significant increase in DC loads (such as data and telecommunication centers) at the power distribution level, an additional set of power electronic converters are required to connect these DC loads to the AC-dominant power network. Notably, hybrid AC/DC microgrids (MGs) serve as promising solutions to satisfying both the AC and DC loads with a reduced number of installed converters. Since DC loads may be randomly distributed in the MG, how to place DC feeders to simultaneously fulfill the economic and security requirements of MG operations remains a challenging problem. To address this issue, this paper proposes a hybrid AC/DC MG planning model to determine the optimal placement of DC feeders with the objective of minimizing the total cost of the investment of distributed energy resources (DERs), converters, and AC/DC distribution lines, as well as the operation of DERs. In particular, the power flow of the hybrid AC/DC MG is derived in a unified manner and then incorporated in the planning model. Eventually, the proposed model suffices to find the optimal number and siting for both DERs and DC feeders while ensuring the continuality of the DC feeders. The proposed model is tested in two MG-based distribution systems, and its effectiveness is validated by the results of numerical experiments.

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Keefer, William, and Maureen Donnelly. "DEVELOPING A WATER MONITORING PROGRAM FOR SECURITY PURPOSES IN WASHINGTON, DC." Proceedings of the Water Environment Federation 2005, no. 9 (January 1, 2005): 6015–21. http://dx.doi.org/10.2175/193864705783814952.

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Chavez-Lugo, Miguel, Claudio R. Fuerte-Esquivel, Claudio A. Canizares, and Victor J. Gutierrez-Martinez. "Practical Security Boundary-Constrained DC Optimal Power Flow for Electricity Markets." IEEE Transactions on Power Systems 31, no. 5 (September 2016): 3358–68. http://dx.doi.org/10.1109/tpwrs.2015.2504870.

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Jovcic, Dragan, Huibin Zhang, David Findlay, AZ Annuar, and Bin Li. "Subsea DC collection grid with high power security for offshore renewables." International Transactions on Electrical Energy Systems 27, no. 2 (August 9, 2016): e2249. http://dx.doi.org/10.1002/etep.2249.

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Lazzari, R., L. Piegari, S. Grillo, M. Carminati, E. Ragaini, C. Bossi, and E. Tironi. "Selectivity and security of DC microgrid under line-to-ground fault." Electric Power Systems Research 165 (December 2018): 238–49. http://dx.doi.org/10.1016/j.epsr.2018.09.001.

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Gatto, Andrea, and Nathan Morrow. "A Life for Development Cooperation, Gender Equality and Food Security—Gretchen Brandow Bloom." Sustainability 14, no. 12 (June 7, 2022): 6947. http://dx.doi.org/10.3390/su14126947.

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Simanjuntak, Herwin, Rully Pramudita, and Nadya Safitri. "Sistem Keamanan Sepeda Motor Menggunakan GPS Dan Radio Frequency Identification (RFID) Berbasis Arduino." Jurnal ICT : Information Communication & Technology 19, no. 2 (January 20, 2021): 47–53. http://dx.doi.org/10.36054/jict-ikmi.v20i2.263.

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Abstract- At this time motorcycle theft cases are still often occur plus the increasing use of motorcycle vehicles, motorcycle theft is caused by the lack of a security system on the ignition which only uses keys and key covers, where security systems like this have been understood mostly motorcycle thieves, the necessity of a motorcycle safety system is needed. To overcome this, a Motorcycle Safety System was made using Arduno-based GPS and Radio Frequency Identification (RFID) to prevent and facilitate the recovery of stolen motor vehicles. The results of this study, the system is made using the Global Positioning System (GPS) as a tool to detect the location of motorcycles, and smart key contacts are added using RFID, SMS gateway and DC-DC Converter.

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Jiang, Hua, Xinglai Shen, and Bing Ma. "A Protection Method for DC Distribution Network with Single Pole Grounding Based on Integrative Two-terminal MMC." Journal of Physics: Conference Series 2066, no. 1 (November 1, 2021): 012104. http://dx.doi.org/10.1088/1742-6596/2066/1/012104.

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Abstract Based on the analysis model of unipolar grounding fault occurred in two-terminal MMC DC distribution network, the characteristics of unipolar grounding fault are studied. The similarity characteristics of transient currents between the fault line and the non-fault line are analyzed when the fault is located in the feeder, tie line and bus respectively. According to the characteristics of single-pole grounding fault and the similarity principle, a new single-pole grounding protection method for DC distribution network based on two-terminal MMC is proposed. The simulation results show that the proposed single-pole grounding protection method can accurately determine the single-pole grounding fault at any position of the DC distribution network. The research results can effectively solve the problem of single-pole grounding protection in DC distribution network, and effectively improve the security and reliability of DC distribution network.

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Zhang, Liang, Kang Chen, Ling Lyu, and Guowei Cai. "Research on the Operation Control Strategy of a Low-Voltage Direct Current Microgrid Based on a Disturbance Observer and Neural Network Adaptive Control Algorithm." Energies 12, no. 6 (March 25, 2019): 1162. http://dx.doi.org/10.3390/en12061162.

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Low-voltage direct current (DC) microgrid based on distributed generation (DG), the problems of load mutation affecting the DC bus under island mode, and the security problems that may arise when the DC microgrid is switched from island mode to grid-connected mode are considered. Firstly, a DC bus control algorithm based on disturbance observer (DOB) was proposed to suppress the impact of system load mutation on DC bus in island mode. Then, in a grid-connected mode, a pre-synchronization control algorithm based on a neural network adaptive control was proposed, and the droop controller was improved to ensure better control accuracy. Through this pre-synchronization control, the microgrid inverters output voltage could quickly track the power grid’s voltage and achieve an accurate grid-connected operation. The effectiveness of the algorithms was verified by simulation.

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Xia, Tian, Xiao Xiao Qi, Li Jun Deng, and Yi Xian Sun. "Modeling & Simulating of Hami-Zhengzhou UHVDC Transmission Project and Security & Stability Analysis of Send-Side Power System." Advanced Materials Research 1070-1072 (December 2014): 790–96. http://dx.doi.org/10.4028/www.scientific.net/amr.1070-1072.790.

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Hami-Zhengzhou ±800kV DC project is the first ultra high-voltage project for Xinjiang power transmission, it is also the first DC transmission project binding thermal and wind power, with bipolar low-end operation in 2013 and bipolar operation in the middle of 2014. The rated power is 8,000MW. This article focused on Hami-Zhengzhou HVDC transmission system, established the electromechanical model, which improved commutation failure treatment in the traditional DC control system and made the simulation results more close to the real operation condition. Based on this model, security and stability analysis of power grid was carried out and the corresponding control strategies/schemes were brought up.

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Hinojosa, Victor H. "Comparing Corrective and Preventive Security-Constrained DCOPF Problems Using Linear Shift-Factors." Energies 13, no. 3 (January 21, 2020): 516. http://dx.doi.org/10.3390/en13030516.

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This study compares two efficient formulations to solve corrective as well as preventive security-constrained (SC) DC-based optimal power flow (OPF) problems using linear sensitivity factors without sacrificing optimality. Both SCOPF problems are modelled using two frameworks based on these distribution factors. The main advantage of the accomplished formulation is the significant reduction of decision variables and—equality and inequality—constraints in comparison with the traditional DC-based SCOPF formulation. Several test power systems and extensive computational experiments are conducted using a commercial solver to clearly demonstrate the feasibility to carry out the corrective and the preventive SCOPF problems with a reduced solution space. Another point worth noting is the lower simulation time achieved by the introduced methodology. Additionally, this study presents advantages and disadvantages for the proposed shift-factor formulation solving both corrective and preventive formulations.

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S.Kom, Ferry Sudarto, Eka Purwandari, and Aldien Sora Andrea. "PROTOTIPE PENGONTROLAN PINTU GUNA MENGAMANKAN NASKAH SOAL UJIAN NASIONAL PADA SMA NEGERI 11 TANGERANG." CCIT Journal 11, no. 1 (February 20, 2018): 82–94. http://dx.doi.org/10.33050/ccit.v11i1.561.

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Research on "PROTOTYPE DOOR CONTROLLING TO SAVE NATIONAL EXAM SCRIPT AT 11 SENIOR HIGH SCHOOL TANGERANG" aims to provide security benefits in the national exam deception problems. This research was carried out by making a prototype in the form of a door with a security system using technologies of embedded systems. Namely to control a door through Android smartphone. This is because the security system is not running optimally so often lead to deception. Therefore, we need a system to facilitate and secure the national examination script . All this time during the security room to store national test script using only a padlock. This research will provide an overview of the complex mechanisms such as how a door will lock securely using an application on Android smarthphone as the key. The prototype uses a door control basic 4 android as an interface between users. By using Bluetooth as a sensor signal to the sender to call the personal computer (pc) database and added arduino uno as a DC motor controllers. Prototype controlling these doors can be a reference to the department in dealing with security issues manuscript national exam

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Watts, M. "Hour of darkness : vulnerability, security and globalization." Geographica Helvetica 57, no. 1 (March 31, 2002): 5–18. http://dx.doi.org/10.5194/gh-57-5-2002.

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Abstract. The events of September 11th in New York and Washington DC have compelled us to focus on the links between globalization and security. I focus on this relationship by exploring the links between food security, vulnerability to hunger and the world market. Using the new book by Mike Davis on late Victorian famines, I show how his political ecology of famine challenges the work of Amartya Sen on entitlements. My contribution examines how and why entitlements need to be deepened and expanded and grounded in a sophisticated understanding of global political economy. Case materials from Africa and India are deployed to illustrate this argument.

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Chandran, Anjana S. "Review on Cryptography and Network Security Zero Knowledge Technique in Blockchain Technology." International Journal of Information Security and Privacy 16, no. 2 (April 1, 2022): 1–18. http://dx.doi.org/10.4018/ijisp.308306.

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A huge amount of data has been generated every day across the world by organizations with the emergence of the World Wide Web, social networks, along with e-commerce applications. To safeguard the network along with data transmission that occurs over a wireless network, cryptography along with network security (NS) is utilized. In data transmission over a wireless untrustworthy network, securing data is a major concern. Providing security to the wireless sensor networks is highly significant; NS provides security not only to the end system but also to all over the network system. Consequently, NS, cryptography, present progress in NS, linear cryptanalysis (LC), together with differential cryptanalysis (DC) are explicated in this work. The outcomes of the encryption time (ET) versus file size for data encryption standard (DES), advanced encryption standard (AES), 3DES, Rivest-Shamir-Adleman (RSA), blowfish, and the decryption time (DT) versus file size for RSA, AES, modified RSA (MRSA), and nth degree truncated polynomial ring units (NTRU) are also evaluated in this paper.

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Qin, Boyu, Wansong Liu, Ruowei Zhang, Jialing Liu, and Hengyi Li. "Review on Short-circuit Current Analysis and Suppression Techniques for MMC-HVDC Transmission Systems." Applied Sciences 10, no. 19 (September 27, 2020): 6769. http://dx.doi.org/10.3390/app10196769.

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The modular multilevel converter (MMC) has been widely adopted in high voltage direct current (HVDC) transmission systems due to its significant advantages. MMC-HVDC is developing towards multi-terminal direct current (MTDC) power grid for reliability enhancement. However, there exist a huge amplitude and a steep rise in fault current due to the low impedances of DC lines and MMCs, which threaten the security and reliability of the DC power grids. It is necessary to restrain the DC short circuit current in order to ensure the safe and stable operation of DC power grids. This paper gives a comprehensive review and evaluation of the proposed DC short-circuit current analysis and suppression techniques used in MMC-based MTDC power girds, in terms of MMC modeling, short circuit calculation, and suppression method. In addition, future trends of countermeasures to short circuit current in MMC-based MTDC power grids are also discussed.

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Autor, David H., Mark Duggan, Kyle Greenberg, and David S. Lyle. "The Impact of Disability Benefits on Labor Supply: Evidence from the VA's Disability Compensation Program." American Economic Journal: Applied Economics 8, no. 3 (July 1, 2016): 31–68. http://dx.doi.org/10.1257/app.20150158.

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Combining administrative data from the US Army, Department of Veterans Affairs, and Social Security Administration, we analyze the effect of the VA's Disability Compensation (DC) program on veterans' labor force participation and earnings. We study the 2001 Agent Orange decision, a unique policy change that expanded DC eligibility for Vietnam veterans who served in theater but did not expand eligibility to other veterans of this era, to assess the causal effects of DC enrollment. We estimate that benefits receipt reduced veterans' labor force participation by 18 percentage points, though measured income net of transfer income rose on average. (JEL H51, I12, I18, J14, J22, J28, J31)

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Hwang, Hyeonseok, Soo Hyoung Lee, Donghee Choi, Sangbong Choi, and Backsub Sung. "Voltage Stability Assessment of a Campus DC Microgrid Implemented in Korea as a Blockchain-Based Power Transaction Testbed." Energies 16, no. 21 (October 27, 2023): 7297. http://dx.doi.org/10.3390/en16217297.

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Recently, the generalization of P2P (peer-to-peer) technology with enhanced security due to blockchain technology and the expansion of renewable energy-based distributed energy resources have led to blockchain technology being applied in power transactions, thus giving the potential to become a new platform for DC microgrid operation. Meanwhile, the voltage of a DC microgrid represents the balance of energy supply and demand and also serves as a stability index. The balance is represented as a steady state; the stability is represented during and after events. This paper examines the stability of the DC microgrid built on a university campus in Korea and, in particular, the blockchain technology-based power transactions performed in the DC microgrid. The test is based on the pre-planned transaction schedule applied in the DC microgrid. The transaction schedule has used day-ahead and real-time bidding data. Although many technologies are included in the project, this paper focuses on the voltage stability of the DC microgrid. In addition, the DC protection is applied and evaluated. To consider general DC protection, the DC breaker was simplified with several IGBTs, diodes, capacitors, and arrestors and was designed to interrupt the fault current within five milliseconds. The stability was evaluated using a PSCAD/EMTDCTM.

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Dehghani, Moslem, Taher Niknam, Mohammad Ghiasi, Navid Bayati, and Mehdi Savaghebi. "Cyber-Attack Detection in DC Microgrids Based on Deep Machine Learning and Wavelet Singular Values Approach." Electronics 10, no. 16 (August 9, 2021): 1914. http://dx.doi.org/10.3390/electronics10161914.

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Nowadays, the role of cyber-physical systems (CPSs) is of paramount importance in power system security since they are more vulnerable to different cyber-attacks. Detection of cyber-attacks on a direct current microgrid (DC-MG) has become a pivotal issue due to the increasing use of them in various electrical engineering applications, from renewable power generations to the distribution of electricity and power system of public transportation and subway electric network. In this study, a novel strategy was provided to diagnose possible false data injection attacks (FDIA) in DC-MGs to enhance the cyber-security of electrical systems. Accordingly, to diagnose cyber-attacks in DC-MG and to identify the FDIA to distributed energy resource (DER) unit, a new procedure of wavelet transform (WT) and singular value decomposition (SVD) based on deep machine learning was proposed. Additionally, this paper presents a developed selective ensemble deep learning (DL) approach using the gray wolf optimization (GWO) algorithm to identify the FDIA in DC-MG. In the first stage, in the paper, to gather sufficient data within the ordinary performance required for the training of the DL network, a DC-MG was operated and controlled with no FDIAs. In the information generation procedure, load changing was considered to have diagnosing datasets for cyber-attack and load variation schemes. The obtained simulation results were compared with the new Shallow model and Hilbert Huang Transform methods, and the results confirmed that the presented approach could more precisely and robustly identify multiple forms of FDIAs with more than 95% precision.

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Weijie, Zheng, Xu Dechao, Chen Yong, Zhang Xing, and Mu Qing. "Multi Step Transient Hybrid Simulation Framework Design and Practical Engineering Application for AC / DC Power Grid." E3S Web of Conferences 256 (2021): 01010. http://dx.doi.org/10.1051/e3sconf/202125601010.

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Based on the large power grid simulation and the existing security prevention and control mode, this paper further integrates the multi-step transient hybrid simulation architecture computing technology to research the high-performance analysis and situational awareness simulation technology of interconnected AC / DC large power grid security and stability characteristics. So as to realize the “panoramic situational awareness, wide area coordinated control, flexible and efficient service” of large power grid, and improve the super large scale power grid Comprehensive security defense and intelligent monitoring level of panoramic, multi-dimensional and three-dimensional.

Journal articles on the topic 'DC Security'

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