京都大学 / 新制・課程博士 / 博士(情報学) / 甲第24034号 / 情博第790号 / 新制||情||134(附属図書館) / 京都大学大学院情報学研究科社会情報学専攻 / (主査)教授 黒田 知宏, 教授 吉川 正俊, 教授 神田 崇行 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

Background. Open source dependencies have become ubiquitous in software development and the risk of regressions during an update are a key concern facing developers. Change impact analysis (CIA) can be used to assess the effects of a dependency update and aid in addressing this challenge. The manual effort required for CIA has created a need to reduce the amount of data that is considered during a compatibility assessment. Formal (mathematical) methods for equivalence analysis have been prolific in previous attempts at minimizing the amount of data that needs to be analyzed. C bounded model checker (CBMC) is an established tool that can perform equivalence verification and a gap in knowledge exists regarding its usefulness for assessing update compatibility. Objectives. The objective of the study was to evaluate how well CBMC could filter out equivalent changes from impact assessments and the relevance of this for dependency updates. A tool named Equivalent update filter (EUF) was developed in the study to tackle this problem. Effectiveness of the tool was assessed based on, (1) the size of reductions that were made possible through filtering, (2) the relevance of the auto-generated verification resources created to perform analysis and (3) the correctness of the results during equivalence analysis. Methods. To assess the reduction capabilities of EUF a controlled experiment regarding the effect of CBMC based equivalence analysis upon impact assessment sizes was conducted. Updates for the experiment were derived from random commit pairs among three C dependencies with established industry use. The relevance of EUF's auto-generated verification resources were measured through an ordinal scale that highlighted the prevalence of different properties in a dependency that would prevent sound equivalence analysis. Soundness of the reductions suggested by EUF was investigated through a comparison with a manually labeled set of updates. Results. The developed filtering approach was able decrease impact assessment sizes by 1 % on average. Considerable differences were observed between the dependencies in the study in regards to analysis time. For each update, 11 % of the auto-generated verification resources were found to be useful for equivalence analysis on average.EUF's classification of equivalent changes was measured to have an accuracy of 67 % in relation to the base truth of manually labeled updates. Conclusions. The study showed that EUF and by extension, CBMC based equivalence analysis, has potential to be useful in dependency compatibility assessments. Follow up studies on different verification engines and with improved methodologies would be necessary to motivate practical use. / Bakgrund. Att använda externa bibliotek med öppen källkod är praxis inom mjukvaruutveckling och risken för uppdateringar att introducera problem är ett betydande orosmoment för utvecklare. Konsekvensanalys, "Change impact analysis" (CIA), kan användas för att utvärdera effekten av en uppdatering och bemöta denna utmaning. Den manuella interaktion som krävs för CIA har medfört att mängden data som analyseras behöver begränsas. Formella (matematiska) metoder för ekvivalensanalys har varit centrala i tidigare försök att minimera analysbehov. "C bounded model checker" (CBMC) är ett etablerat verktyg för C som kan utföra ekvivalensanalys och tidigare forskning har inte studerat dess relevans för kompatibilitetsbedömning vid beroende uppdateringar. Syfte. Denna studies syfte var att utvärdera CBMC's förmåga att filtrera bort ekvivalenta ändringar från uppdateringar av externa beroenden. Verktyget "Equivalent update filter" (EUF) utvecklades under projektet för att uppnå syftet. Effektiviteten av EUF bedömdes med hjälp av tre kriterier, (1) storleken på de reduktioner som möjliggjordes av filtrering, (2) relevansen av de autogenererade resurser som skapades för att utföra ekvivalensanalys och (3) korrektheten av de resultat som erhölls från ekvivalensanalys. Metod. EUF's reduktionsförmåga undersöktes genom ett kontrollerat experiment där inverkan av CBMC baserad ekvivalensanalys på analysbehovet för olika uppdateringar analyserades. Uppdateringarna som användes för experimentet hämtades från tre olika C bibliotek med bred användning i industrin. Värdet av EUF's autogenererade resurser studerades i relation till hur ofta de medförde negativa konsekvenser på korrektheten av ekvivalensanalysen. Korrektheten hos de reduktioner som EUF utförde under experimenten mättes genom en jämförelse med ett antal manuellt klassificerade uppdateringar. Resultat. Den utvecklade filtreringsmetoden hade en förmåga att minska mängden data som behöver analyseras med 1 % i genomsnitt. Exekveringstiden varierade kraftigt mellan de olika bibliotek som testades. För varje uppdatering så bedömdes i genomsnitt 11 % av de autogenererade verifieringsresurserna vara användbara för ekvivalensanalys. EUF's detektion av ekvivalenta och icke-ekvivalenta förändringar visades ha en träffsäkerhet på 67 % i relation till manuella klassificeringar. Slutsatser. Studien fann att EUF och i förlängningen, CBMC baserad ekvivalensanalys, har potential att vara en användbar del av kompatibilitetsbedömningar för beroende uppdateringar. En uppföljningsstudie med andra verifikationsverktyg och förbättrade metoder hade varit nödvändiga för att motivera praktisk användning.

As the power industry enters the new century, powerful driving forces, uncertainties and new services and functions are compelling electric utilities to make dramatic changes in the way they communicate. Expanding network services such as real time monitoring are also driving the need for more increasing bandwidth in the communication network backbone. These needs will grow further as new remote real-time protection and control applications become more feasible and pervasive. This dissertation addresses two main issues for the future power system information infrastructure: communication network infrastructure and associated power system applications. Optical network no doubt will become the predominate network for the next generation power system communication. The rapid development of fiber optic network technology poses new challenges in the areas of topology design, network management and real time applications. Based on advanced fiber optic technologies, an all-fiber network was investigated and proposed. The study will cover the system architecture and data exchange protocol aspects. High bandwidth, robust optical network could provide great opportunities to the power system for better service and efficient operation. In the dissertation, different applications were investigated. One of the typical applications is the SCADA information accessing system. An Internet-based application for the substation automation system will be presented. VLSI (Very Large Scale Integration) technology is also used for one-line diagrams auto-generation. High transition rate and low latency optical network is especially suitable for power system real time control. In the dissertation, a new local area network based Load Shedding Controller (LSC) for isolated power system will be presented. By using PMU and fiber optic network, an AGE (Area Generation Error) based accurate wide area load shedding scheme will also be proposed. The objective is to shed the load in the limited area with minimum disturbance. / Ph. D.

With the simulations tools available today, simulation can be utilised as a platform for more advanced software testing. By introducing simulations to software testing of robot controllers, the motion performance testing phase can begin at an earlier stage of development. This would benefit all parties involved with the robot controller. Testers at ABB would be able to include more motion performance tests to the regression tests. Also, ABB could save money by adapting to simulated robot tests and customers would be provided with more reliable software updates. In this thesis, a method is developed utilising simulations to create a test set for detecting motion anomalies in new robot controller versions. With auto-generated test cases and a similarity analysis that calculates the Hausdorff distance for a test case executed on controller versions with an induced artificial bug. A test set has been created with the ability to detect anomalies in a robot controller with a bug.

Electricity power is an irreplaceable resource in industry for a country. Enough and steady-offered electricity is also the support to develop not only traditional industry but high technology industry. Taiwan is a place, where is lacking of natural resources. There is only 3 % of which can be self ¡Vcontained. In fact, electricity power plays one of important roles in achieving ¡§Economic Miracle of Taiwan.¡¨ Basically, electricity power embraces three parts of power generation, power transmission, and distribution. And it is managed by the way of vertically integration. Traditionally, electricity power is assorted into public utility because of its huge principal and social resources, even concerning with the economy and society of the country and is governed and controlled by the government. Whatever country promotes electricity liberalization, the government and the academic put their eye on foster the total efficiency of management through market mechanisms. Electricity liberalization has been working for more than twenty years. Of course, there are some successful cases, for example, like England, Australia, and etc. They do benefit from increasing the occurrence, the efficiency, and decrease the price after operating electricity liberalization. As to Taiwan, the government has the same policy on it, too. The amendments are under discussion in The Legislative Yuan. By referencing to electricity liberalization of other countries and comparing their experiences with Taiwan, the questions below are searched in this thesis. First, does the policy in Taiwan really satisfy the essence of electricity liberalization? Second, could power generation, power transmission, and distribution of the electricity industry be operated by vertically integrated way? After electricity liberalization, it is important that how to do could get good combined with competition of the market, the offer of steady electricity and the society justice. If not, how to modify the rules would satisfy the needs of country development and expectations of the society.

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