Utility Accrual (UA) scheduling is a method of dynamic real-time scheduling that is designed to respond to overload conditions by producing a feasible schedule that heuristically maximizes a pre-defined metric of utility. Whereas utility accrual schedulers have traditionally focused on CPU overload, this dissertation explores memory overload conditions during which the aggregate memory demand exceeds a system's available memory bandwidth. Real-time systems are typically implemented in C or other languages that use explicit dynamic memory management. Taking advantage of modern type-safe languages, such as Java, necessitates the use of garbage collection (GC). The timeliness requirements of real-time systems, however, impose specific demands on the garbage collector. Garbage collection introduces a significant source of unpredictability in the execution timeline of a task because it unexpectedly interjects pauses of arbitrary length, at arbitrary points in time, with an arbitrary frequency. To construct a feasible schedule, a real-time scheduler must have the ability to predict the collector's activities and plan for them accordingly. We have devised CADUS (Collector-Aware Dynamic Utility Scheduler), a utility accrual algorithm that tightly links CPU scheduling with the memory requirements -and the corresponding garbage collection activities - of real-time tasks. By constructing and storing memory time allocation profiles, we address the problem of GC activation strategy. We estimate GC latency by using a real-time collector and modeling its behavior. We project GC frequency by planning, at schedule construction time, the memory bandwidth available to the collector. CADUS can point the collector's activities to any specific task in the system. The runtime system provides this ability by maintaining separate logical heaps for all tasks. We demonstrate the viability of CADUS through extensive simulation studies. We evaluated the behavior of CADUS under a wide range of CPU and memory load conditions and utility distributions. We compared its performance against an existing GC-unaware UA scheduler and found that CADUS consistently outperformed its GC-unaware counterpart. We investigated and identified the reasons for the superior performance of CADUS and quantified our results. Most significantly, we found that in an overloaded dynamic soft real-time system, a scheduler's preemption decisions have a highly significant impact on GC latency. A dynamic real-time scheduler therefore must predict the impact of its preemption decisions on GC latency in order to construct time-feasible schedules. / Ph. D.

The traditional block-based interface used in flash-based Solid State Drives (SSDs) imposes limitations on performance and endurance due to write amplification and garbage collection overheads. In response to these challenges, the NVMe Zoned Namespaces (ZNS) devices introduces a novel storage interface organized into zones, optimizing garbage collection and reducing write amplification. This research delves into the exploration and profiling of ZNS device characteristics, aiming to enhance user comprehension and utilization. Additionally, the study investigates the integration of ZNS devices into disaggregated storage frameworks to improve resource utilization, proposing server-side management features to simplify client operations and minimize overhead. By offering insights for future development and optimization of ZNS-based storage solutions, this work contributes to advancing storage technology and addressing the shortcomings of traditional block-based interfaces. Through extensive experimentation and analysis, this study sheds light on the optimal configurations and deployment strategies for ZNS-based storage solutions. / Master of Science / Traditional storage drives, like those found in computers and data centers, face challenges that limit their performance and durability. These challenges stem from the way data is stored and managed within these drives, resulting in inefficiencies known as write amplification and garbage collection overheads. To address these issues, a new type of storage device called NVMe Zoned Namespaces (ZNS) has been developed. ZNS devices organize data in a smarter way, grouping it into specific areas called zones. This organization helps to reduce inefficiencies and improve performance. This research explores the characteristics of ZNS devices and how they can be used more effectively. By better understanding and using these devices, we can improve the way data is stored and accessed, leading to faster and more reliable storage solutions. Additionally, this research looks at how ZNS devices can be integrated into larger storage systems to make better use of available resources. Ultimately, this work contributes to advancing storage technology and overcoming the limitations of traditional storage interfaces. We aim to uncover the best ways to deploy and optimize ZNS-based storage solutions for a variety of applications.

Implementing a Prolog Runtime System in a language like Java which provides its own automatic memory management and safety features such as built--in index checking and array initialization requires a consistent approach to memory management based on a simple ultimate goal: minimizing total memory management time and extra space involved. The total memory management time for Jinni is made up of garbage collection time both for Java and Jinni itself. Extra space is usually requested at Jinni's garbage collection. This goal motivates us to find a simple and practical garbage collection algorithm and implementation for our Prolog engine. In this thesis we survey various algorithms already proposed and offer our own contribution to the study of garbage collection by improvements and optimizations for some classic algorithms. We implemented these algorithms based on the dynamic array algorithm for an all--dynamic Prolog engine (JINNI 2000). The comparisons of our implementations versus the originally proposed algorithm allow us to draw informative conclusions on their theoretical complexity model and their empirical effectiveness.

As the development of hardware progresses, computers are expected to solve increasingly complex problems. However, solving more complex problems requires more complex software. To be able to develop these software systems, new programming languages with new features and higher abstraction levels are introduced. These features are designed to ease development, but sometimes they also make the runtime behavior unpredictable. Such features can not be used in real-time systems. A feature that traditionally has been unpredictable is garbage collection. Moreover, even though a garbage collector frees unused memory, almost all such methods require large amounts of additional memory. Garbage collection relieves developers of the responsibility to reclaim memory that is no longer used by the application. This is very tedious and error prone if done manually. Since garbage collection increases productivity and decreases programming errors, developers find it attractive, also in the real-time domain. This thesis presents a predictable garbage collection method, real-time reference counting, that increases memory efficiency by about 50 % compared to the most memory efficient previously presented predictable garbage collector. To increase performance, an optimization technique called object ownership that eliminates redundant reference count updates is presented. Object ownership is designed for reference counters, but can also be used to increase the performance of other incremental garbage collectors. Finally, a static garbage collector is presented. The static garbage collector can allocate objects statically or on the runtime stack, and insert explicit instructions to reclaim memory allocated on the heap. It makes it possible to eliminate the need for runtime garbage collection for a large class of Java applications. The static garbage collection method can also be used to remove costly synchronization instructions. Competing static garbage collection methods with reasonable analysis time are restricted to stack allocation, and thus handle a smaller class of applications.

Moderne, objektorientierte Sprachen spielen bei der Entwicklung von Software für eingebettete Systeme bislang kaum eine Rolle. Die Gründe hierfür sind vielfältig, meist wird jedoch die mangelnde Effizienz und der größere Speicherbedarf hervorgehoben. Obwohl Java viele Eigenschaften hat, die sehr für einen Einsatz in eingebetteten Systemen sprechen, so hängt doch gerade Java vielfach immer noch das Vorurteil an, in Systemen mit beschränkter Rechenleistung und Speicher zu viele Ressourcen zu benötigen. Diese Arbeit soll dazu beitragen, diese Vorurteile abzutragen. Sie stellt insbesondere Techniken vor, die den Speicherbedarf einer JVM so gering wie möglich halten und diese effizient mit der zur Verfügung stehenden Rechenleistung umgehen lassen. Viele der dargestellten Verfahren und Algorithmen wurden in der Kertasarie VM implementiert, einer virtuellen Maschine, die speziell für den Einsatz in eingebetteten Systemen konzipiert wurde. Durch die weit verbreitete Vernetzung eingebetteter Systeme über das Internet stellt sich in vielen Fällen zudem das Problem einer modernen, abstrakten und effizienten Form der Kommunikation. Aus diesem Grund liegt der zweite Schwerpunkt dieser Arbeit auf dem Vergleich von objektorientierten Middleware-Architekturen, insbesondere von Java-RMI. Auch auf diesem Gebiet wird eine eigene, speziell an eingebettete Systeme angepasste RMI-Variante vorgestellt. / Modern, object oriented languages do not play an important role when developing software for embedded systems. There are many reasons for it, most often an inadequate performance and a greater memory demand are mentioned. In spite of the fact that Java has many features suitable for embedded systems, Java often faces the prejudice to consume too much resources in systems with limited processing power and memory. This work is a contribution to diminish this prejudices. It presents techniques to limit the memory demands of a Java Virtual Machine and to effectively cope with limited computing power. Many of the presented methods and algorithms are implemented in the Kertasarie VM, a JVM designed to run in embedded systems.Due to the fact of increasing network capabilities embedded systems often face the problem of a modern, abstract and efficient communication. Therefore the second emphasis of this work is put on the comparison of object oriented middleware architectures, especially Java-RMI. An own implementation for embedded systems is also presented.

Bakgrund och problem:         Målstyrning, som utvecklades inom den privata sektorn, blev som en följd av New Public Management (NPM) ett vanligt styrsätt inom svenska kommunorganisationer redan i början av 1990-talet. Skillnader i förutsättningarna mellan privata och offentliga organisationer har sedan dess gjort att det funnits svårigheter att tillämpa styrsättet. Tidigare forskning har identifierat problem i form av målträngsel, målformulering, mätbarhet och uppföljning. Studier som fokuserat på beslut i kommunorganisationer har bland annat tittat på tjänstemanna- kontra politikerrollen och individernas egenskaper. I den här studien dockas de båda områdena samman då beslut under kommunala organisationers målprocesser studeras med särskilt fokus på individers påverkan på besluten. Forskningsfråga:                        Hur påverkar individer i en kommunorganisation, i praktiken, de beslut om mål och delmål som förekommer under målstyrda arbeten? Och varför ser påverkan ut som den gör? Syfte:                                              Syftet med studien är att förklara individers påverkan på beslut om mål och delmål under ett målstyrt arbete i en kommunorganisation, detta för att skapa en helhetsbild som ökar den totala förståelsen för målarbeten i dessa organisationer. Teoretisk referensram:           Studien koncentreras kring individers påverkan på beslut, genom att ta utgångspunkt i den vidareutvecklade Garbage-Can-teorins begrepp; problem, lösningar, tid, engagemang och möjligheternas fönster. Samtliga delar inriktas på målstyrda kommunorganisationers förutsättningar, genom att de beskrivs med utgångspunkt i tidigare forskning kring NPM, målstyrning samt individers roller och egenskaper. Ett praktikteoretiskt perspektiv används för att länka samman delarna till en förklarande helhet. Metod:                                           Arbetet har genomförts som en kvalitativ fallstudie och empiriinsamlingen har i första hand gjorts genom direkta observationer under mötestillfällen i en kommunal målprocess. Slutsatser:                                    Studien har visat att individer i målstyrda kommunorganisationer påverkar beslut om mål och delmål genom att argumentera för olika problem och lösningar och agera med skiftande tidsinsats och engagemang. Detta i sin påverkan av målförslagen, arbetsfördelningen och beslutsprocessen. Att påverkan ser ut på detta sätt beror enligt vår studie på att den, tillsammans med den sociala värld där den ägt rum, är en del av en ömsesidigt grundläggande helhet. Den sociala verkligheten är formad av flera strukturella och politiska förutsättningar som både påverkas av individerna och som påverkar dem. / Background and problems:   Management by objectives was developed in the private sector and became, with the help of New Public Management (NPM), a commonly used mode of control in Swedish municipalities in the early 1990s. Different prerequisites between private and public organizations have made the implementation problematic all from the beginning. Previous research has identified problems with goal inflation, goal writing, measurability and monitoring. Studies of decision making in municipal organizations has focused on the roles of officials and politicians and the characteristics of these individuals. This study brings the two areas together by focusing on decisions during municipal goal processes and the impact of the individuals on the decisions made in these processes. Research question:                   How do the individuals in a municipal organization, in practice, affect the decisions of objectives that occur during work managed by objectives? And why does the affect appear this way? Purpose:                                        The purpose of this study is to explain the individual’s impact on objectives set for a municipal work managed by objectives; this will help to create an overall picture that increases the understanding of goal processes in this kind of organizations. Frame of reference:                 The study concentrates on individual’s impact on decisions by starting off from the concepts of the extended Garbage Can theory; problems, solutions, time, dedication and windows of opportunity. By being described in relation to previous research of NPM, MBO and the roles and characteristics of individuals, these components where oriented towards the conditions of a municipal organization managed by objectives. Practice Theory has been used to link the concepts together to a holistic explanation. Method:                                        This study was made as a qualitative case study where the empirical data collection where made primarily through direct observations during meetings in a municipal goal process. Conclusions    The study has shown that individuals in municipal organizations managed by objectives affect decisions of objectives by arguing in favor of different problems and solutions and acting with shifting time effort and dedication. This in their effect on the suggested objectives, the division of labor and the decision process. According to this study, the affect appears this way because it is, together with the social world that surrounds it, a part of a mutual constitution. The social world is formed by both structural and political conditions that are being affected by the individuals as well as they affect them.

No description available.

Orientador: Bruno Coraucci Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-26T11:21:28Z (GMT). No. of bitstreams: 1 Buda_JoseFrancisco_D.pdf: 7168261 bytes, checksum: b9f15e39a51e5f756266765a99ec4830 (MD5) Previous issue date: 2014 / Resumo: A Política Nacional de Resíduos (PNRS), instituída pela Lei nº 12305 de 02 de agosto de 2010 e regulamentada pelo Decreto n° 7.404 de 23 de dezembro de 2010, apresenta a importância do tripé entre Poder Público, Empresas e Sociedade na gestão dos resíduos sólidos, incentivando a participação das cooperativas de catadores de material reciclável no processo de recebimento/coleta, triagem, enfardamento e comercialização dos materiais, como também pode-se destacar a importância que estas desempenham na inclusão social e geração de renda. Esta pesquisa teve como objetivo avaliar efeitos causados pela PNRS, nas condições e no ambiente de trabalho das cooperativas, as mudanças ocorridas nas relações com as empresas e sociedade quanto ao volume e qualidade dos resíduos recebidos, e com os órgãos municipais. Foram pesquisadas as cooperativas conveniadas com a Prefeitura do Município de São Paulo, onde estas responderam um formulário que levantou as variáveis: ambientais e sanitárias, econômicas, institucionais, infraestrutura e de saúde e segurança no trabalho. Foram entrevistados os presidentes das cooperativas, pois estes são os cooperados mais antigos e alguns até participarão na redação da lei. Foi possível assim retratar as condições das cooperativas e também conclui-se assim que a PNRS se configura como modeladora de novos paradigmas sociais, dentre os quais se destacam os princípios de responsabilidade social compartilhada e que as mudanças comportamentais pretendidas pelo documento legal não deverão ser obtidas de forma rápida, mas sim de forma gradual em avanços sucessivos. A aceleração deste processo somente será dada com o incremento da fiscalização e do apoio do poder público à questão da reciclagem, o que garantirá a efetividade da lei / Abstract: The National Waste Policy (PNRS), established by Law No. 12305 of August 2, 2010 and regulated by Decree No. 7,404 of December 23, 2010, shows the importance of the tripod between Government, the Companies and Society in waste management solid, encouraging the participation of waste pickers cooperatives in the receiving process / collection, sorting, baling and marketing of materials, but also can highlight the importance they play in the social inclusion and income generation. This research aimed to evaluate effects caused by PNRS under the conditions and in the work environment of cooperatives, changes in relationships with business and society about the size and quality of the waste received, and municipal agencies. The cooperatives were surveyed with the city of São Paulo City Hall, where they answered a form that lifted the variables: environmental, sanitary, economic, institutional, infrastructure, health and safety at work. We interviewed the presidents of cooperatives, as these are the oldest cooperative and some even participate in drafting the law. It was this possible to portray the conditions of cooperatives and concluded as soon as the PNRS is configured as shaping of new social paradigms, among which stand out the principle of shared social responsibility, required behavioral changes by the legal document should not be obtained quickly, but gradually in successive advances. The acceleration of this process will only be given to increasing the supervision and government support to the issue of recycling, which will ensure the effectiveness of the law / Doutorado / Saneamento e Ambiente / Doutor em Engenharia Civil

Course: Master Thesis in Business Administration Institution: Business School at Linneus University in Växjö Authors: Nadja Muftic and Donika Ombashi Supervisor: Karin Jonnergård Examiner: Fredrik Karlsson Title: Integrated reporting  - The glass half full or half empty? Background: Integrated reporting is the latest framework in the reporting world and intends to integrate financial and non-financial information into one single report. Through the <IR> framework, the integrated report aims to describe how business strategies, corporate governance and performance create value over short, medium and long-term perspective. The integrated report has gained enthusiasm and attention in media and among experts in Sweden. Despite the good presentation of integrated reporting, there are only a few companies in Sweden that publish integrated reports in accordance with the <IR> framework. The discourse, the overall discussion, about the phenomenon is therefore interesting to examine among companies in Sweden. Purpose: The purpose of this thesis is to study the discourse of integrated reporting among experts in Sweden and the relevance of the discourse amongst Swedish companies. Furthermore, we also intend to explain the circumstances that affect the relevance between the discourse and the companies. Method: This thesis consists of two studies; a first study that examines the discourse on integrated reporting developed by experts in Sweden and a second study that examines the relevance of the discourse amongst Swedish companies. A qualitative approach is the basis of the two studies, in which the collected material has been obtained through semi-structured interviews. The expert’s discourse has been processed through a critical discourse analysis and the material from the companies has been processed through a content analysis. Conclusion: The conclusion is that the discourse has a low relevance amongst companies in Sweden at the moment. However, the identified circumstances that explain the relevance indicate that the phenomenon may spread more in the future. / Kurs: Examensarbete Civilekonomprogrammet Lärosäte: Linnéuniversitetet i Växjö Författare: Nadja Muftic och Donika Ombashi Handledare: Karin Jonnergård Examinator: Fredrik Karlsson Titel: Integrerad rapportering – Glaset halvfullt eller halvtomt? Bakgrund: Integrerad rapportering är det senaste inom rapporteringsvärlden och avser att integrera finansiell- och icke finansiell information till en enskild rapport. Genom ramverket <IR> ämnar den integrerade rapporteringen beskriva hur företagsstrategier, styrning och prestationer skapar värde över kort, medellång, och lång sikt. Den integrerade rapporteringen har erhållit entusiasm och uppmärksamhet i media och bland experter i Sverige. Trots den goda framställningen av integrerad rapportering finns det idag i Sverige ett fåtal företag som publicerar integrerade rapporter enligt ramverket <IR>. Diskursen, den samlade diskussionen, kring fenomenet är därmed intressant att undersöka på företagsnivå. Syfte: Syftet med denna uppsats är att studera diskursen om integrerad rapportering bland experter i Sverige och vilken relevans diskursen har på företagsnivå. Vidare ämnar vi även förklara omständigheter som påverkar om det finns en relevans eller inte mellan diskurs och företag.               Metod: Denna uppsats utgörs av två studier; en första studie som undersöker den diskurs om integrerad rapportering som framkommit bland experter i Sverige och en andra studie som undersöker diskursens relevans på företagsnivå. En kvalitativ forskningsansats ligger till grund för båda studierna där det insamlade materialet har erhållits genom semistrukturerade intervjuer. Experternas diskurs har bearbetats genom en kritiskdiskursanalys och materialet från företagen har bearbetats med hjälp av en innehållsanalys. Slutsats: Slutsatsen dras att diskursen har en låg relevans på företagsnivå i Sverige i nuläget. De identifierade omständigheterna som förklarar relevansen tyder dock på att fenomenet kan få en större utbredning i framtiden.

Moderne, objektorientierte Sprachen spielen bei der Entwicklung von Software für eingebettete Systeme bislang kaum eine Rolle. Die Gründe hierfür sind vielfältig, meist wird jedoch die mangelnde Effizienz und der größere Speicherbedarf hervorgehoben. Obwohl Java viele Eigenschaften hat, die sehr für einen Einsatz in eingebetteten Systemen sprechen, so hängt doch gerade Java vielfach immer noch das Vorurteil an, in Systemen mit beschränkter Rechenleistung und Speicher zu viele Ressourcen zu benötigen. Diese Arbeit soll dazu beitragen, diese Vorurteile abzutragen. Sie stellt insbesondere Techniken vor, die den Speicherbedarf einer JVM so gering wie möglich halten und diese effizient mit der zur Verfügung stehenden Rechenleistung umgehen lassen. Viele der dargestellten Verfahren und Algorithmen wurden in der Kertasarie VM implementiert, einer virtuellen Maschine, die speziell für den Einsatz in eingebetteten Systemen konzipiert wurde. Durch die weit verbreitete Vernetzung eingebetteter Systeme über das Internet stellt sich in vielen Fällen zudem das Problem einer modernen, abstrakten und effizienten Form der Kommunikation. Aus diesem Grund liegt der zweite Schwerpunkt dieser Arbeit auf dem Vergleich von objektorientierten Middleware-Architekturen, insbesondere von Java-RMI. Auch auf diesem Gebiet wird eine eigene, speziell an eingebettete Systeme angepasste RMI-Variante vorgestellt. / Modern, object oriented languages do not play an important role when developing software for embedded systems. There are many reasons for it, most often an inadequate performance and a greater memory demand are mentioned. In spite of the fact that Java has many features suitable for embedded systems, Java often faces the prejudice to consume too much resources in systems with limited processing power and memory. This work is a contribution to diminish this prejudices. It presents techniques to limit the memory demands of a Java Virtual Machine and to effectively cope with limited computing power. Many of the presented methods and algorithms are implemented in the Kertasarie VM, a JVM designed to run in embedded systems.Due to the fact of increasing network capabilities embedded systems often face the problem of a modern, abstract and efficient communication. Therefore the second emphasis of this work is put on the comparison of object oriented middleware architectures, especially Java-RMI. An own implementation for embedded systems is also presented.