The ongoing wireless communication evolution offers improvements for industrial applications where traditional wireline solutions causes prohibitive problems in terms of cost and feasibility. Many of these new wireless applications are packet oriented and time-critical. The deadline dependent coding (DDC) communication protocol presented here is explicitly intended for wireless real-time applications. The objective of the work described in this thesis is therefore to develop the foundation for an efficient and reliable real-time communication protocol for critical deadline dependent communication over unreliable wireless channels. Since the communication is packet oriented, block codes are suitable for error control. Reed-Solomon codes are chosen and incorporated in a concatenated coding scheme using iterative detection with trellis based decoding algorithms. Performance bounds are given for parallel and serially concatenated Reed-Solomon codes using BPSK. The convergence behavior of the iterative decoding process for serially concatenated block codes is examined and two different stopping criteria are employed based on the log-likelihood ratio of the information bits. The stopping criteria are also used as a retransmission criterion, incorporating the serially concatenated block codes in a type-I hybrid ARQ (HARQ) protocol. Different packet combining techniques specifically adapted to the concatenated HARQ (CHARQ) scheme are used. The extrinsic information used in the iterative decoding process is saved and used when decoding after a retransmission. This technique can be seen as turbo code combining or concatenated code combining and is shown to improve performance. Saving the extrinsic information may also be seen as a doping criterion yielding faster convergence. As such, the extrinsic information can be used in conjunction with traditional diversity combining schemes. The performance in terms of bit error rate and convergence speed is improved with only negligible additional complexity. Consequently, CHARQ based on serially concatenated block codes using iterative detection creates a flexible and reliable scheme capable of meeting specified required realtime constraints.

No description available.

No description available.

A real-time application is designed as a set of tasks with specific timing attributes and constraints. These tasks can be categorized as periodic, sporadic or aperiodic, based on the timing attributes that are specified for them which in turn define their runtime behaviors. To ensure correct execution and behavior of the task set at runtime, the scheduler of the underlying operating system should take into account the type of each task (i.e.,  periodic, sporadic, aperiodic). This is important so that the scheduler can schedule the task set in a predictable way and be able to allocate CPU time to each task appropriately in order for them to achieve their timing constraints. ENEA OSE is a real-time operating system with fixed priority preemptive scheduling policy which is used heavily in embedded systems, such as telecommunication systems developed by Ericsson. While OSE allows for specification of priority levels for tasks and schedules them accordingly, it can not distinguish between different types of tasks. This thesis work investigates mechanisms to build a scheduler on top of OSE, which can identify three types of real-time tasks and schedule them in a more predictable way. The scheduler can also monitor behavior of task set at run-time and invoke violation handlers if time constraints of a task are violated. The scheduler is implemented on OSE5.5 soft kernel. It identifies periodic, aperiodic and sporadic tasks. Sporadic and aperiodic tasks can be interrupt driven or program driven. The scheduler implements EDF and RMS as scheduling policy of periodic tasks. Sporadic and aperiodic tasks can be scheduled using polling server or background scheme. Schedules generated by the scheduler  deviate from expected timing behavior due to scheduling overhead. Approaches to reduce deviation are suggested as future extension of thesis work. Usability of the scheduler can be increased by extending the scheduler to support other scheduling algorithm in addition to RMS and EDF. / CHESS

The effective oversight and management of national emergencies are critical to preserving democratic processes and norms. Congress passed the National Emergencies Act (NEA) of 1976 to regulate the open-ended and unchecked implementation of emergency authorities by the president. Notwithstanding the NEA's objectives, the number and duration of national emergencies are proliferating. National emergencies evoke a sense of urgency that results in exceptional governance procedures and alters official and public perceptions. However, national emergencies declared under the NEA rarely reflect the definition of urgency and endure for years, indicating potential oversight failures and a re-emergence of the president's unchecked use of emergency power. Concerns arise that a national emergency shifts legislative power to the executive, making government policy less democratic. The national scope of these emergencies also portends the potential for harm to a broad population. Ambiguous judicial and legislative instructions, presidential aspirations of demonstrating leadership, and congressional blame avoidance further complicate the governance of national emergencies. This research conceptualizes time as the intelligible principle that Congress used to meet the judicial requirements for delegating functional responsibilities to the executive branch while retaining constitutional obligations and maintaining oversight of executive action. Sequences, deadlines, and repetition are temporal mechanisms that help regulate government action and moderate authorities. Understanding how temporal policy mechanisms affect the use of emergency authority, shape government interaction, and adjust accountability is particularly important as the United States confronts a hyper-partisan environment and demands to confront new issues as national emergencies intensify. Employing a policy tracing methodology augmented by survival and qualitative comparative analysis, this dissertation analyzes national emergency data composed of declarations, continuations, amendments, and terminations. The analysis incorporates Supreme Court decisions, budgetary impact statements, and Federal Register data to track and evaluate national emergencies declared via presidential proclamation and executive order. The ensuing model delineates the properties of the national emergencies declared under the NEA and clarifies relational factors contributing to temporal variation amongst emergency declarations. The resulting clarity contributes to scholarly and governmental use of temporal policy mechanisms—particularly sequences, deadlines, and repetition—and offers recommendations for enhancing the oversight of U.S. national emergencies. / Doctor of Philosophy / The oversight and management of national emergencies are crucial for protecting democratic processes and norms. In 1976, Congress passed the National Emergencies Act (NEA) to prevent the president from using unconstrained emergency powers. However, the NEA has not been successful in controlling the frequency and duration of national emergencies. During a national emergency, a sense of urgency generally leads to exceptional governance procedures and changes how people perceive governance situations. This research examined national emergency declarations, continuations, amendments, and terminations to understand how the NEA governs emergencies and what principles guide it. The findings show that national emergencies declared under the NEA have limited congressional oversight and are increasingly influenced by politics. The lack of clear instructions from the judiciary and the legislature, the president's desire to display leadership, and Congress' tendency to avoid blame further complicate the governance of national emergencies, allowing them to last for many years without proper oversight. To address the weaknesses in the NEA and improve the handling of national emergencies, this dissertation proposes the concept of temporal policy mechanisms. Temporal policy mechanisms use time as a guiding principle to delegate emergency authority and ensure accountability. Examples of temporal mechanisms include sequences, deadlines, and repetition to regulate government actions and moderate authorities. The analysis also highlights origination bias, where Congress sets rules for others but fails to follow its own processes. By implementing transparent temporal policy mechanisms and reducing the sense of urgency during prolonged national emergencies, accountability and transparency can be enhanced thereby upholding U.S. constitutional principles and benefiting they citizenry.

Annotation The diploma thesis deals with the description and analysis of tax and administrative management in terms of deadlines. The aim of the thesis is to find a practical basis when applying an inconsistent setting of deadlines in the tax and administrative procedures. It was important to determine whether the concept of deadlines in the legislation is different, how the concept of time is regulated in the legislation and how this issue can actually affect us. The analysis of individual management was based on actual data. I was provided the data related to the tax procedure by a particular tax subject. The data related to the administrative procedure were requested from a specific administrative authority. The practical part of the thesis deals with a detailed analysis of individual management in terms of deadlines. The tax procedure was about determining the preclusion of the deadline for a tax assessment and the identification of the factors which had an impact on the course of this period. In the case of administrative proceeding, the time limits which are necessary for discussion of the minor offense and the administrative offense were analyzed. The thesis contains tables with data for better clarity within individual management.

Scheduling is extremely important for modern real-time systems. It enables several programs to run in parallel and succeed with their tasks. Many systems today are real-time systems, which means that good scheduling is highly needed. This thesis aims to evaluate the real-time scheduling algorithm earliest deadline first, newly introduced into the Linux kernel, and compare it to the already existing real-time scheduling algorithms first in, first out and round robin in the context of firm tasks. By creating a test program that can create pthreads and set their scheduling characteristics, the performance of earliest deadline first can be evaluated and compared to the others. / Schemaläggning är extremt viktigt för dagens realtidssystem. Det tillåter att flera program körs parallellt samtidigt som deras processer inte misslyckas med sina uppgifter. Idag är många system realtidssystem, vilket innebär att det finns ett ytterst stort behov för en bra schemaläggningsalgoritm. Målet med det här examensarbetet är att utvärdera schema-läggningsalgoritmen earliest deadline first som nyligen introducerats i operativsystemet Linux. Målet är även att jämföra algoritmen med två andra schemaläggningsalgoritmer (first in, first out och round robin), vilka redan är väletablerade i Linux kärnan. Det här görs med avseende på processer klassificerade som firm. Genom att skapa ett program som kan skapa pthreads med önskvärda egenskaper kan prestandan av earliest deadline first algoritmen utvärderas, samt jämföras med de andra algoritmerna.

En grafisk designer måste kunna producera oavsett vilka förhållanden som råder. Rapporten behandlar vad korta och långa deadlines har för inverkan på denna förmåga och hur kreativiteten kan främjas vid stressiga situationer. Semistrukturerade djupintervjuer utfördes med åtta Art- och Creative directors i Gävledala-regionen för att undersöka hur de upplevde att vara kreativa under stressiga förhållanden. Resultatet visade att det generellt inte var ett problem för studiens respondenter att vara kreativa på beställning men att de inte heller följde några specifika metoder för att underlätta arbetsflödet. Det visade sig även att det snarare var arbetsbördan och mängden arbetsuppgifter som påverkade stressfaktorn än en specifik tidsram. / A graphic designer must be able to create and produce regardless of conditions. The present study addresses what impact short and long deadlines have on this ability and how creativity can be encouraged in stressful situations. Semistructured interviews were conducted with eight Art and Creative directors in GävleDala region to examine how they felt about being creative under stressful conditions. The results showed that there is generally not a problem for the interviewees to be creative on demand, but they do not follow any specific methods to ease the workflow. It was also found that it was rather the workload and the amount of assignments that affect the stress factor rather than a specific time frame.

Recently, online group-buying has been a popular business model. It was observed that many characteristics of online group-buying are potential stimuli of impulse buying. Therefore, we target traditional online group-buying and e-coupon group-buying and try to explore the characteristics of online group-buying stimulating impulse buying. Based on the literature review and empirical data collection, we identified five characteristics of online group-buying which may stimulate impulse buying. They are group-buying discount, time pressure, social interaction, perceived shopping convenience and consumption deadline. The data were collected through online questionnaire. The analysis result shows that the five characteristics of online group-buying indeed cause impulse buying. Further, we also explored whether the impulse buying behavior will be moderated in different situations. These moderators include group-buying model (traditional online group-buying vs. e-coupon group-buying), transaction price level, relationship with the group-buying initiator, product type and group-buying experience. The result indicates that the impulse buying behaviors are easier to be stimulated in the following situations: traditional online group-buying, lower transaction price, familiar with the traditional online group-buying initiator, non-food product and more experienced consumers of online group-buying.

The time/cost trade-off models in project management aim to compress the project completion time by accelerating the activity durations at an expense of additional resources. The budget problem in discrete time/cost trade-off scheduling selects the time/cost mode -among the discrete set of specified modes- for each activity so as to minimize the project completion time without exceeding the available budget. There may be alternative modes that solve the budget problem optimally, however each solution may have a different total cost value. In this study we aim to find the minimum cost solution among the optimal solutions of the budget problem. We analyze the structure of the problem together with its linear programming relaxation and derive some mechanisms for reducing the problem size. We solve the reduced problem by linear programming relaxation and branch and bound based approximation and optimization algorithms. We find that our branch and bound algorithm finds optimal solutions for medium-sized problem instances in reasonable times and the approximation algorithms produce high quality solutions. We also discuss the way our algorithms could be used to construct the time/cost trade-off curve.