Dissertations / Theses on the topic 'Small scale electronic device'

La récupération d'énergie à petite échelle pour alimenter les appareils électroniques autoalimentés se développe considérablement. À cet égard, la possibilité de combiner la récolte thermique et mécanique à l'aide de matériaux intelligents fait l'objet d'une plus grande attention. Nous avons présenté la faisabilité de l'utilisation d'un polymère piézoélectrique P(VDF-TrFE) couplé à un alliage à mémoire de forme (AMF) NiTi pour récolter à la fois l'énergie mécanique et thermique dans des dispositifs évolutifs simples. Un composite multicouche AMF-P(VDF-TrFE) a été élaboré et a démontré ses performances électro-thermo-mécaniques. Nous avons conçu un banc expérimental pour effectuer la caractérisation électro-thermomécanique du composite, permettant de mesurer la réponse piézoélectrique lorsqu'il est soumis à un chauffage et un refroidissement périodique. De plus, nous avons réalisé l'analyse par éléments finis du composite AMF/Piézoélectrique et simulé les principales propriétés du SMA telles que le comportement super-élastique, l'effet de mémoire de forme unidirectionnel et l'effet de mémoire de forme bidirectionnel, pour finalement identifier le comportement électro-thermomécanique effectif global du composite AMF-polymère piézoélectrique. Enfin, afin de récolter efficacement la charge électrique générée à partir du film P(VDF-TrFE), nous avons étudié et comparé deux types de convertisseurs élévateurs intégrés, et déterminé les conditions pour une collecte d’énergie effective. Ces résultats sont prometteurs et montrent la faisabilité de ce composite multicouche pour alimenter de manière autonome de petits appareils électroniques tels que des capteurs sans fil, des MEMS et des dispositifs biomédicaux
Small-scale energy harvesting to power self-powered electronic devices is tremendously increasing. In this regard, the ability to combine thermal and mechanical harvesting using smart materials pays more attention. We have presented the feasibility of using P(VDF-TrFE) piezoelectric polymer coupled with NiTi shape memory alloy (SMA) to harvest both mechanical and thermal energy in simple scalable devices. A novel multi-layered SMA-P(VDF-TrFE) composite was fabricated and carried out their electro-thermo-mechanical performance. We have designed and developed an experimental bench to perform the electro-thermomechanical characterization of the composite, allowing us to measure the piezoelectric response when it is subjected to periodic heating and cooling. Furthermore, we performed the finite element analysis of the SMA-Piezoelectric composite and simulated the main properties of SMA such as superelastic behavior, one-way shape memory effect, and two-way shape memory effect, to finally identify the overall effective electro-thermomechanical behavior of the SMA-piezoelectric polymer composite. Finally, in order to efficiently harvest the electric charge generated from the P(VDF-TrFE) film, we have studied and compared two types of integrated converters and determined the conditions for effective energy harvesting. These results are promising, which showing the feasibility of this multilayered composite to power small electronics such as wireless sensors, MEMS and biomedical devices in an autonomous way

This work presents the concept development, implementation and first practical demonstration of a new pressure intensifier for energy recovery in small-scale seawater reverse osmosis systems, and the simplified system configuration it requires. The new concept has great potential to reduce the specific energy consumption of small-scale seawater reverse osmosis systems. A mathematical analysis to study pressure intensifiers for energy recovery in reverse osmosis applications was developed. The analysis was used in the design and modelling of the energy recovery device. A first prototype was built and subsequently demonstrated in a system desalinating seawater over a wide range of electrical input power stretching between 286 and 1196 W, producing up to 286 L/h of freshwater with specific energy consumptions in the range of 3.5 to 4.5 kWh/m^3. The flat specific energy characteristic makes the device attractive for renewable-energy-powered systems without energy storage. The prototype implementation was realised through modifying a Clark pump, but the new concept is fundamentally different. The new device recovers energy from the concentrate stream, which it then uses to suck in and pressurise seawater, relying purely on its piston area ratio, and thus eliminating the need for a low-pressure feed pump.

Smart devices have become more commonplace in the past years, surpassing mobile phones in use. Partially, this rise can be attributed to the possibility of customizing the devices with new software, which in turn are easier to create. These applications exists for many purposes, allowing new ways for the users to create and share their experiences but also provide useful services, such as GPS enabled navigation. Augmented reality (AR), meaning the addition of virtual information to the real world in a seamless manner, can be explored with the devices as well. AR requires a combination of specific hardware, that are found in compact smart devices, to be functional. Smart devices, with their large displays and cameras allow vision based detection and visual presentation of augmentations. AR applications enable smart devices to function as a “magnifying glass” to the underlying data of the observed objects or locations. This thesis explores the new paradigm of interaction that AR allows on smart devices. This is achieved through the construction of an Android smart device application, utilizing free or open source software development tools. The main application concept features linking of user specified instances, objects or locations, to information that the user associates with the instances. By using the application, the user can create, modify and detect the added information from their environment. The research was initiated by exploring the literature related to the research domain and performing a review of the existing AR applications available on Android devices. The knowledge from the existing literature and reviews was used to formalize the research question and to define the thesis’s limitations. As the creation of a new application was the principal target of this thesis, Systems Development Research (SDR), a research approach relating and contributing to Design Science (DS), was chosen to be utilized. The application was designed with the use of scenarios, that detailed the key features that the system should implement. The scenarios were used in the evaluation of the application as well, by identifying the deviation from the design that had occurred during the implementation. Volunteers also used the scenarios to evaluate how well the key features were implemented within the application. The applications performance and stability were also evaluated. The results of the evaluation show that the application implements the features described in the scenarios, with volunteers stressing the importance of feedback from the application to improve its use. The application is also shown to be stable and developed conforming to the design guidelines and requirements expected of it. The creation of a AR smart device application using vision based detection requires identification of the systems requirements and the capabilities of the software development tools. For vision based detection, OpenCV offers comprehensive and cross-platform capable libraries, which can be used to implement the required AR functions.

As more and more renewable energy sources like wind and solar power are added to the electricgrid, reliable sources of power like hydropower become more important. Hydropower isabundant in Scandinavia, and helps to maintain a stable and reliable grid with added irregularitiesfrom wind and solar power, as well as more fluctuations in demand. Aside from the reliabilityaspect of hydropower, power producers want to maximize their profit from sold electricity. InSweden, power is bid to the spot market at Nord Pool every day, and a final spot price is decidedwithin the electricity market. There is a different electricity price each hour of the day, so it ismore profitable to generate power during some hours than others.There are many other factors that can change when it is most profitable for a hydropower plant tooperate, like how much local inflow of water there is. Hydropower production is an ideal case forusing optimisation models, and they are widely used throughout industry already. Though theoptimisation calculations are done by a computer, there is a lot of manual work from the spottraders that goes into specifying the inputs to the model, such as local inflow, price forecasts, andperhaps most importantly, market strategy. Due to the large amount of work that needs to be donefor each hydropower plant, many of the smaller power plants are not optimised at all, but are leftto run on an automatic control that typically tries to maintain a constant water level. In Fortum,this is called, VNR, or vattennivåreglering (water level regulation).The purpose of this thesis is to develop an optimisation algorithm for a small hydropower plant,using Fortum owned and operated Båthusströmmen as a test case. An optimisation model is builtin Fortum’s current modelling system and is tested for 2016. In addition, a mathematical model isalso built and tested using GAMS. It is found that by optimising the plant instead of running it onVNR, an increase of about 15-16% in profit could be seen for the year 2016. This is a significantimprovement, and is a strong motivator to being optimising the small hydropower plants.Since the main reason many small hydropower plants are not optimised is because it takes toomuch of employees time, a second phase of this thesis was conducted in conjunction with twoother students, Jenny Möller and Johan Wiklund. The focus of this portion was to develop acentralized controller to automatically optimise the production schedule and communicate withthe central database. This would completely remove the workload from the spot traders, as wellas increase the overall profit of the plant. This thesis describes the results from both the Fortummodel and the GAMS model, as well as the mathematical formulation of the GAMS model. Thebasic structure of the automatic controller is also presented, and more can be read in the thesis byMöller and Wiklund (Möller & Wiklund, 2018).
Tillförlitliga energikällor som vattenkraft blir allt viktigare vart eftersom elkraftsystemet utökasmed fler förnybara energikällor som vindkraft och solenergi. I Norden finns det rikligt medvattenkraft, vilket bidrar till att upprätthålla ett stabilt och pålitligt elnät även med ökadeoregelbundenheter från vindkraft och solkraft samt större variationer i efterfrågan. Bortsett frånvattenkraftens tillförlitlighetsaspekter vill kraftproducenter maximera sin vinst från såld el. ISverige läggs dagligen bud på effektvolym till spotmarknaden Nord Pool och ett slutgiltigtmarknadspris bestäms därefter av elmarknaden. Varje timme under dygnet motsvarar ett enskiltelpris, därmed är det mer lönsamt att generera effekt under de timmar där priset är som högst.Det finns många andra faktorer som påverkar när det är mest lönsamt för ett vattenkraftverk attproducera el, exempelvis hur stort det lokala inflödet av vatten är. Vattenkraftproduktion är idealtför tillämpning av optimeringsmodeller, vilka är vanligt förekommande inom verksamhetsområdet.Även om optimeringsberäkningarna utförs av en dator innebär optimeringen mycket manuelltarbete för Fortums elhandlare som specificerar indata till modellen. Exempel på indata är lokaltinflöde, prisprognoser och kanske viktigast av allt marknadsstrategi. På grund av den storamängden arbete som fordras för varje vattenkraftverk, optimeras inte produktionen för många avde småskaliga kraftverken utan de regleras automatiskt med mål att upprätthålla en konstantvattennivå. Denna typ av reglering kallas vattennivåreglering, VNR.Syftet med examensarbetet var att utveckla en optimeringsalgoritm för ett småskaligtvattenkraftverk, där Fortumägda vattenkraftverket Båthusströmmen används som testobjekt. Enoptimeringsmodell utvecklades i Fortums befintliga system och testades för 2016. Dessutom haren matematisk modell utvecklats och testades med GAMS. Det konstaterades att genom attoptimera produktionen från vattenkraftverket istället för att reglera den via VNR kan envinstökning med cirka 15-16 % för noteras år 2016. Detta är en väsentlig förbättring och är ettstarkt argument för att optimera produktionen från småskaliga vattenkraftverk.Eftersom den främsta orsaken till att många småskaliga vattenkraftverk inte optimeras är denutökade arbetsbelastningen det skulle innebära för de anställda, genomfördes en andra fas iexamensarbetet i samverkan med två andra studenter, Jenny Möller och Johan Wiklund. Fokus fördenna del var att utveckla en centraliserad styrenhet för att automatiskt optimera produktionsplaneroch kommunicera med det befintliga centrala systemet. Detta innebär att utökad arbetsbelastningenfrån elhandlarna undviks, samt öka vattenkraftverkets totala vinst. Denna rapport beskriverresultaten från både Fortum-modellen och GAMS-modellen, liksom den matematiskaformuleringen av GAMS-modellen. Även grundstrukturen för det självreglerandeoptimeringsverktyget presenteras, mer kan läsas i rapporten av Möller och Wiklund (Möller &Wiklund, 2018).Nyckelord: Optimering, vattenkraftplanering, självreglerande, automatisk styrning, optimalplanering

With the continuous trend of drying climate it has become evident that water scarcity is becoming a bigger issue then it was decades ago. It is particularly affecting isolated settlements such WA’s farmlands, which are in need of essential water supply and are far away from the main cities. Therefore, an alternative water supply solution was to implement a small-scale RO unit with the integration of an automated blending device, as the combination of the two sources (permeate & feed) increases the volume of existing water supply at a much-reduced cost. This thesis project involves the redevelopment of a bench scale-blending device to further optimise the performance of the device by testing two control strategies developed to enhance the effectiveness of the device in achieving the end user’s desires. The developed and tested control strategies were the Bang Bang control strategy and the Time-Proportional PID control strategy that was constructed using a software known as the Arduino IDE. Three main tests that were conducted including a Precision & Accuracy test; the Speed test and the Setpoint Change Tracking Ability test, which assess the ability of the program to meet the desired objectives. The findings of the trials carried out evaluated that each control strategy has its own advantages and disadvantages. Therefore, to determine the “better” strategy of the two depends on the end user (farmer) of the device and the setting in which the device will be implemented. It was concluded that the Bang Bang control strategy was most suitable for short-term use due to its switching mechanism of the solenoids and that the Time-Proportional PID control strategy was more preferable for long-term application. However, for this device to be tested on field scale it requires further research to be done on the different blending techniques suitable for this context as the current blending technique employed will not be adequate for an onsite application.

The focus of this thesis is the integration of distributed MPPT solutionswith existing photovoltaic systems. Power electronics are used to optimizethe output power from solar panels. Different topologies are used where adc/dc converter carries out the optimization task for one or more strings ofsolar panels. When connected in series, the same current flows through allthe panels. Shading and mismatch lead to sub-optimal operation, not only ofsingle panels but of every panel connected to the string. The installation ofoptimizers on all panels might prove to be a way to mitigate the power lossdue to mismatch, shading and faulty panels.The main goal of this thesis was to evaluate the performance of a PV plantusing a combination of a PV string optimizer and single panel optimizers. Themethod for this thesis consisted of field experiments, where the power outputwas measured for an existing PV plant with a string inverter. Two strings wereused, a control string with only the string optimizer and a test string usingpanel optimizers. The tests were conducted under various shading scenarios.The results show that there is an increase of between 1−3% energy productionusing panel optimizers.
Det här examensarbetet behandlar frågan om att integrera distribuerade MPPT-lösningar med redan existerande solcellssystem. Kraftelektroniska kom- ponenter och metoder används för att optimera effektutmatningen från solcel- ler. Ett antal olika utformningar används där en DC/DC omvandlare utför optimeringen av en eller flera solcellssträngar. När solceller är seriekopplade går samma ström genom samtliga paneler. Vid skuggning eller felmatchning leder detta till att inte bara den individuella panelen utan samtliga paneler i en sträng kommer att drivas under icke-optimala förhållanden. Att installera optimerare kan visa sig vara ett sätt att avhjälpa förluster i effektutmatningen som uppstår på grund av felmatchning, skuggning och trasiga paneler. Huvudmålet i det här examensarbetet var att utvärdera prestandan hos en solcellsanläggning genom att använda en kombination av solcellsoptimerare avsedda för hela solcellssträngar och solcellsoptimerare avsedda för individuella paneler. Som metod genomfördes praktiska fältförsök varvid kraftutmatningen mättes hos en redan existerande solcellsanläggning med solcellsoptimerare. Två strängar användes vid dessa undersökningar, en kontrollsträng med endast en strängoptimerare och en experimentsträng där individuella strängoptimerare användes. Testerna utfördes under olika skuggningsförhållanden. Resultaten visar på att ene med 1-3% genom att använda sol-cellsoptimerare.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2011.
"February 2011." Cataloged from PDF version of thesis.
Includes bibliographical references (p. 14).
Current methods of producing pharmaceutical compounds are large batch processes. The minimum time-to-patient for drug manufacturing is approximately 100 days. Using a continuous manufacturing process, the time-to-patient could be reduced to less than ten days. The scope of this paper encompasses the design of a machine for the desiccation of a mixture of solvent and pharmaceutical compound. The goal of this project was to provide a small-scale, high throughput method of continuous pharmaceutical drug drying for Novartis-MIT Center for Continuous Manufacturing. Specifications included a product flow rate of 100 grams per hour and a final product form of flowable powder. Several machines were built and tested, with the final design being comprised of a convective drum dryer and a modular continuous vacuum dryer.
by Eric Owen Correll.
S.B.

Research on two-dimensional (2D) materials currently occupies a sizeable fraction of the materials science community, which has led to the development of a comprehensive body of knowledge on such layered structures. However, the goal of this thesis is to deepen the understanding of the comparatively unknown heterostructures composed of different stacked layers. First, we utilise linear-scaling density functional theory (LS-DFT) to simulate intricate interfaces between the most promising layered materials, such as transition metal dichalcogenides (TMDC) or black phosphorus (BP) and hexagonal boron nitride (hBN). We show that hBN can protect BP from external influences, while also preventing the band-gap reduction in BP stacks, and enabling the use of BP heterostructures as tunnelling field effect transistors. Moreover, our simulations of the electronic structure of TMDC interfaces have reproduced photoemission spectroscopy observations, and have also provided an explanation for the coexistence of commensurate and incommensurate phases within the same crystal. Secondly, we have developed new functionality to be used in the future study of 2D heterostructures, in the form of a linear-response phonon formalism for LS-DFT. As part of its implementation, we have solved multiple implementation and theoretical issues through the use of novel algorithms.

This thesis describes the fabrication and characterization of two-dimensional transition dichalcogenides (2D TMDs) nanolayers for various applications in electronic and opto-electronic devices applications. In Chapter 1, crystal and optical structure of TMDs materials are introduced. Many TMDs materials reveal three structure polytypes (1T, 2H, and 3R). The important electronic properties are determined by the crystal structure of TMDs; thus, the information of crystal structure is explained. In addition, the detailed information of photon vibration and optical band gap structure from single-layer to bulk TMDs materials are introduced in this chapter. In Chapter 2, detailed information of physical properties and synthesis techniques for molybdenum disulfide (MoS2), tungsten disulfide (WS2), and molybdenum ditelluride (MoTe2) nanolayers are explained. The three representative crystal structures are trigonal prismatic (hexagonal, H), octahedral (tetragonal, T), and distorted structure (Tʹ). At room temperature, the stable structure of MoS2 and WS2 is semiconducting 2H phase, and MoTe2 can reveal both 2H (semiconducting phase) and 1Tʹ (semi-metallic phase) phases determined by the existence of strains. In addition, the pros and cons of the synthesis techniques for nanolayers are discussed. In Chapter 3, the topic of synthesized large-scale MoS2, WS2, and MoTe2 films is considered. For MoS2 and WS2 films, the layer thickness is modulated from single-layer to multi-layers. The few-layer MoTe2 film is synthesized with two different phases (2H or 1Tʹ). The all TMDs films are fabricated using two-step chemical vapor deposition (CVD) method. The analyses of atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL), and Raman spectroscopy confirm that the synthesis of high crystalline MoS2, WS2, and MoTe2 films are successful. The electronic properties of both MoS2 and WS2 exhibit a p-type conduction with relatively high field effect mobility and current on/off ratio. In Chapter 4, vertically-stacked few-layer MoS2/WS2 heterostructures on SiO2/Si and flexible polyethylene terephthalate (PET) substrates is presented. Detailed structural characterizations by Raman spectroscopy and high-resolution/scanning transmission electron microscopy (HRTEM/STEM) show the structural integrity of two distinct 2D TMD layers with atomically sharp van der Waals (vdW) heterointerfaces. Electrical transport measurements of the MoS2/WS2 heterostructure reveal diode-like behavior with current on/off ratio of ~ 104. In Chapter 5, optically uniform and scalable single-layer Mo1-xWxS2 alloys are synthesized by a two-step CVD method followed by a laser thinning. Post laser treatment is presented for etching of few-layer Mo1-xWxS2 alloys down to single-layer alloys. The optical band gap is controlled from 1.871 to 1.971 eV with the variation in the tungsten (W) content, x = 0 to 1. PL and Raman mapping analyses confirm that the laser-thinning of the Mo1-xWxS2 alloys is a self-limiting process caused via heat dissipation to SiO2/Si substrate, resulting in fabrication of spatially uniform single-layer Mo1-xWxS2 alloy films.

Changes in the environment are a major area of concern to any firm in its strategic decision making process (SDMP). SDMP is considered to be an important component in the success of firms in the strategic management literature. This includes small and medium-sized enterprises (SMEs) operating in the electronic, telecom and information technology (IT) sector which are subjected to frequent and extremely dynamic environments both internally and externally, unlike many other industries. A lack of prior studies supporting an understanding of the SDMP in SMEs is evident, and coupled with the extremely volatile environmental conditions that compound the problem, makes SMES dealing in electronic, telecom and IT products and services highly vulnerable to closure. An immediate investigation into the SDMP in SMEs is needed and long overdue. This research seeks to address this gap in the knowledge. In order to address the gap this research used synoptic formalism and incrementalism to develop an understanding on how SMEs in the electronic, telecom and IT sector make decisions and what is the nature of these decisions. A Strategic Decision Making Process (SDMP) model was developed based on prior research. Decision magnitude of impact acted as the input to the SDMP, rationality and intuition acted as the process component, and decision process output as the output component. Thus these three concepts acted as the three components of a process (input-process-output) configuration. The model facilitated the development of an understanding of the functioning of decision magnitude of impact as a decision characteristic factor, its relationship to SDMP and process dimensions (rationality in decision making and intuition) as an antecedent (and hence as a predictor) of decision output variables (decision process effectiveness), quality of the decision process output through the mediation of decision dimensions. In line with the need to understand the SDMP in SMEs data were collected from managers of a large number of SMEs belonging to electronic, telecom and IT sector. The territory chosen was the Gulf Cooperation Council countries (Kingdom of Bahrain, Kingdom of Saudi Arabia, Kuwait and United Arab Emirates) as this region provides a rich source of such SMEs and the environment is highly dynamic. A self-administered questionnaire was developed by adapting previously validated questionnaire scales. Pre-testing and pilot surveys were used to ensure that the contents, format and scales were appropriate. A range of decision makers in those SMEs were targeted. 464 valid questionnaires were returned, representing a response rate of over 50%. The data was coded and analysed using SPSS/AMOS, two widely used statistical software tools. The data analysis steps included reliability and validity testing (Cronbach’s alpha and Confirmatory Factor Analysis, respectively). The entire model was tested using Structural Equation Modelling (SEM). Using SEM it was possible to identify the model, test the parsimonious nature of the model, determine whether the identified model makes theoretical sense and examine the fitness of the model to the data. The predictability of decision process output by decision magnitude of impact was analysed using path analysis as part of the SEM. The research outcome showed that in the electronic, telecommunication and information technology sector, where the environment is dynamic, decision magnitude as an important independent variable influences rationality in decision making directly and decision effectiveness, quality of decision process output and firm commitment indirectly. Rationality in decision making was found act as an important medicating variable in the strategic decision making process. In the same vein it was found that intuition is not affected by decision magnitude of impact. Further, dynamism in the industry and firm performance were also seen to influence decision effectiveness, quality of decision process output and firm commitment although the influence of dynamism in the industry on firm commitment was found to be very low. Thus the main contribution of this research is the development of an understanding of the relationship between decision magnitude of impact as input to the SDMP and hence as predictor of decision process output and the SDMP process output. Furthermore, the research has advanced current knowledge on the influence of rationality in decision making and intuition as mediators between decision magnitude of impact and decision process output variables. These two aspects have been tested in an SME sector that is affected seriously by dynamism in the industry and with varying firm performance as a contextual feature. The comprehensive research outcome can be of benefit to the SMEs in the electronic, telecom and IT sector and support them in overcoming potential vulnerabilities by making strategic decisions whose magnitude of impact on the firms is high and a decision process that is rational. In addition from the point of view of methodology this research has used SEM in understanding the nature and functioning of the model as well as the operationalisation of the variables. The outcome of this research is expected to benefit the SMEs in the electronic, telecom and IT sector in their SDMP and has opened up a new area of research for other researchers and academics.

Småskaliga vattenkraftverk regleras vanligtvis med avseende på vattennivån i magasinet eller vattenflödet, utan hänsyn till efterfrågan på elkraft. Examensarbetet utfördes på uppdrag av Fortum Generation som önskade att undersöka möjligheten att istället automatiskt optimera planeringen och regleringen av de småskaliga vattenkraftverken med hänsyn till prisbild, verkningsgrad, vattensituation, miljödomar, miljöhänsyn samt mekaniskt slitage. En optimeringsalgoritm framtagen i en parallellt pågående studie låg till grund för examensarbetet. En prototyp som skulle autoplanera produktionen och reglera ett enskilt vattenkraftverk skulle utvecklas, där det genom simulering skulle fastställas om en realisering av optimeringsalgoritmen i ett verktyget är möjlig och lönsam. Båthusströmmen, som användes som testobjekt för examensarbetet, ägs av Fortum och är ett småskaligt vattenkraftverk i Österdalälven. En kostnadseffektiv prototyp av ett optimeringsverktyg för automatisk planering och reglering av småskaliga vattenkraftverk utvecklades och testades genom simulering. Prototypen utvecklades i form av en mjukvara vilken utför optimeringen och kommunicerar kontinuerligt med befintliga optimerings-, övervaknings- och styrsystem. Resultaten av utförda kommunikationstester och simulerade optimeringar visade att en realisering av algoritmen i ett optimeringsverktyg är möjlig och förväntas öka effektiviteten för Båthusströmmen och därmed öka intäkterna för kraftverket.
Small-scale hydropower plants are usually controlled considering either the reservoir level or the water flow, regardless of the electricity demand. This thesis was conducted on behalf of Fortum Generation that wanted to investigate the possibility to automatically optimise the production plans and control of small-scale hydropower plants based on electricity price, generator efficiency, water situation, environmental restrictions, environmental concerns, and mechanical wear. The thesis is a continuation of a study where an optimisation algorithm was developed. A prototype that could automatically plan the production and control of an individual hydropower plant would be developed, and then based on simulations it would be determined if an implementation of the algorithm in an optimisation tool is possible and profitable. Båthusströmmen, the test case for this thesis, is owned by Fortum and is a small-scale hydropower plant in Österdalälven. A cost-effective prototype of an optimisation tool for automated planning and control was developed and tested through simulations. The prototype was developed as a software that performs the optimisation and communicates continuously with the existing optimisation, supervisory and control system. The results of the communication tests and optimisation simulations showed that an implementation of the algorithm in an optimisation tool is possible and is expected to increase the efficiency of Båthusströmmen and therefore increase the profit of the power plant.

This study had two specific aims: Firstly, to determine whether or not, within a given group of subjects in a school in Kwa-Zulu Natal, the mediation offered during an application of Feuerstein's Learning Potential Assessment Device (LPAD) in a group-administration format would result in modified cognition, demonstrated by improved performance in post-mediation testing; and secondly, to determine whether in the same group of subjects, the group-administration format of the LPAD would detect differences in the degree of cognitive modifiability of individuals. Feuerstein's LPAD follows a pretest - mediation - post-test procedure in which, by comparing pretest performance with post-test performance, the effects of the mediation, and hence the degree of cognitive modifiability of the individuals concerned, are determined. The present study operationalised Feuerstein's concept of Mediated Learning Experience (Feuerstein, 1979; 1980) and Vygotsky's concepts of mediation and internalisation (Vygotsky, 1978; Wertsch, 1985) by making use of Tharp and Gallimore's means of assistance within the zone of proximal development (Tharp and Gallimore, 1988). The pretest phase of the three selected instruments (Numerical Progressions, Organizer and Complex Figure Drawing Test), was administered to a group of twenty one black, female, high-school pupils. On the basis of their performance, the subjects were divided into matched experimental and control groups. In a second session, two weeks later, the experimental group received mediation in the cognitive operations and functions required by the instruments. Immediately following this, the post-test phase was administered to both groups. The scores of the subjects in each group were analysed: the scores of the experimental group as a whole were compared-to the scores of the control group, and the pretest scores of each subject were compared to her post-test scores in each instrument. In Numerical Progressions and Organizer, a significant increase in the post-mediation scores of the experimental group was observed, while the scores of the control group remained approximately at pre-mediation levels. The results of the Complex Figure Drawing Test did not follow the same pattern, however, due to difficulties inherent in both the instrument itself and the process of mediation. An analysis of the post-test scores of individual subjects in the experimental group revealed that some improved significantly, some a little, and some even performed less well on the post-test than on the pretest. It was postulated that this variability in post-test scores was an indication of the various degrees of modifiability of the subjects concerned, demonstrating the ability of these instruments, even in a group administration format, to begin to identify levels in the cognitive modifiability of individuals. The items in Numerical Progressions and Organizer were also categorised according to their levels of difficulty. An examination of the performance of subjects at the various levels gave further evidence of both the efficacy of the mediation and the degrees of cognitive modifiability of individuals.
Thesis (M.Ed.)-University of Natal, Pietermaritzburg, 1996.

碩士
國立臺灣大學
商學研究所
89
Small and medium-scale enterprises in Taiwan always played very important roles during the economical development . When Taiwan was faced with difficult challenges , they showed good flexibility at the right moment . According to information provided by Institute for Information Industry , however , the electronic maturity of industries in Taiwan was lowest among four Asian countries — Singapore , Hong Kong , South Korea and Taiwan . Although we can’t understand what benefits e-business could bring , one thing that we’re sure is enterprises will be eliminated through competition if they don’t transfer e-business . For this reason , small and medium-scale enterprises of Taiwan should transfer e-business positively to cope with keen international competition . E-business has been a inevitable trend . This research adopted deep interviews on Honmyue Enterprise Co., Ltd. , Cybergate Corporation , Long Da Construction Co., Ltd. ,Ho Feng Industry Co., Ltd. and Whale Industry Co., Ltd. . The research also used qualitative analysis to discuss e-business’s motivation , its implement , its benefits , its barriers and some other issues of the government’s role during the process which small and medium-scale enterprises of Taiwan transferred e-business and success factors of e-business . Concerning the motivation of e-business , this research found that motivations and needs have many differences among different industries and enterprises , but two events that Taiwan will enter into World Trade Organization and China has more and more powerful science and technology have made small and medium-scale enterprises transfer e-business positively . Concerning the implement of e-business , this research found that five interviewed corporations all implemented in proper sequence and from up to down . Concerning the benefits of e-business , this research found that improvement of efficiency is the common point of this research and literatures . In addition , improvement of enterprise image is an unexpected benefit by interviewed corporations and never mentioned in the literatures . Concerning the barriers of e-business , this research found that the resistance from employees is the most serious . Concerning the government’s role , this research found that five interviewed corporations all indicate negative evaluations , including careless guidance and passive attitude . Concerning the success factors of e-business , this research found that determination of the boss is the most important , and this result conforms with literatures . According to the above-mentioned results , this research established twenty-one propositions to be the basis for future follow-up studies .

An energy harvesting device driven by aeroelastic vibration with self-sustained pitching and heaving using an induction based power take off mechanism has been designed and tested for performance under various operating conditions. From the data collected the results show that the device achieved a maximum power output of 48.3 mW and a maximum efficiency of 2.26% at a dimensionless frequency of 0.143. For all airfoils tested the device was shown to be self-starting above 3 m/s. A qualitative description relating to the performance of the device considering dynamic stall and the flow conditions at optimal dimensionless frequency has been proposed and related to previous work. Performance for angles off the wind up to 22 degrees and was observed to have no reduction in power output due to the change in angle to the wind. The device has shown evidence of having a self-governing capability, tending to decrease its power output for heavy windpspeeds, a thorough examination of this capability is recommended for future work.
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碩士
樹德科技大學
資訊工程系碩士班
106
The purpose of this study is to investigate the impact of electronic textbooks on the achievement of Chinese learning for elementary school third-grade students. A quasi-experimental time sequential design is adopted in this research. The subjects of the experiment are 12 small-scale elementary school third-grade students, taught by the researcher. The traditional and experimental teachings are conducted for 8 weeks 64 classes, repectively. The experimental results are statistically analyzed. The use of traditional paper and pen teaching and experimental teaching of electronic textbooks will last for 8 weeks and 64 lessons in total. Before and after the teaching experiment, the evaluation scores are taken as the pretest and posttest results respectively. After the teaching experiment, the students are asked to fill in the questionnaire. According to the analysis of the pretest, the posttest, and questionnaire results, the research conclusions are as follows: 1. Using electronic textbooks to assist teaching in elementary school has a positive impact on students’ Chinese learning achievements. 2. The use of electronic textbooks can help students improve their Chinese learning motivation. 3. After using electronic textbooks, the elementary school third-grade students’ satisfaction about Chinese learning is improved. The questionnaire results show that students highly recognize that the integration of electronic textbooks into Chinese teaching can improve learning achievements and motuvation. And after learning, they are more confident and interested. This study provides specific suggestions for the reference of future Chinese teaching and related research.

碩士
樹德科技大學
資訊工程系碩士班
106
The purpose of this study is to explore the impact of the integrating electronic textbooks into English teaching on Elementary school students’ learning achievements and motivation. To understand how the students’ learning is changed by using electronic textbooks in English classes, a quasi-experimental time sequential design is adopted. The subjects of the experiment are 10 second grade students, 7 boys and 3 girls, taught by the researcher, conducting a six-week experiment. The teaching materials used are the 3rd to 5th lessons of Kang Xuan''s Super Starter Book 1. The research process is based on quantitative data analysis. Before and after the teaching experiment, the first and second periodic evaluation scores are taken as the pretest and posttest results respectively. After the teaching experiment, the students are asked to fill in the "Electronic Textbook Integrating into English Teaching Questionnaire". The results are statistically analyzed using SPSS. In addition, this study is supplemented by qualitative data. The Student Interview Outline is recorded as a reference for researchers to modify the instructional design. The research results are as follows: 1.The use of electronic textbooks integrating into English teaching can help students improve their English learning achievements. 2.The use of electronic textbooks integrating into English teaching can help students improve their English learning motivation. 3.Students are positive about the use of electronic textbooks integrating into English teaching.

This thesis comprises three essays on “The Economic impact of adult mortality and morbidity on smallholder farm households in Malawi.” The first essay estimates the levels of technical efficiency of AIDS-affected and non-affected smallholder farm households, and examines the technical efficiency differentials. The study uses time-varying and timeinvariant inefficiency models of production. The results show that among both female and male headed households, for both affected and non-affected households, fertilizer and seeds are the only variables that contribute significantly towards technical efficiency. The mean efficiency levels of affected and non-affected households are statistically not different. The second essay examines the maize production differentials between AIDS-affected and nonaffected farm households using the difference in difference estimation method. The results show that, for both affected and non-affected households, the mean maize production levels are higher during 2006/07 compared to 2004/05 However, the difference between the mean maize production levels of affected and non-affected households over the 2004/05 and 2006/07 period is not statistically significant. The third essay examines the coping strategies used by households facing food security problems. The results from the multinomial logistic model show that during 2004/05 and 2006/07, the most dominant coping strategy used by both AIDS-affected and non-affected households facing food security problems, is buying food from market. This is followed by casual labour, obtaining food from relatives and friends, eating unripe maize before harvest, and irrigation farming. The results from logistic discriminant analysis function indicate that, for all households, ordinary coping strategies are dominant among food-insecure households with a total score of close to 80 percent, much higher than survival strategies at around 20 percent during 2004/05.
Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2011.