Exponential bounds on error probability with Feedback

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 95-97).Feedback is useful in memoryless channels for decreasing complexity and increasing reliability; the capacity of the memoryless channels, however, can not be increased by feedback. For fixed length block codes even the decay rate of error probability with block length does not increase with feedback for most channel models. Consequently for making the physical layer more reliable for higher layers one needs go beyond the framework of fixed length block codes and consider relaxations like variable-length coding, error- erasure decoding. We strengthen and quantify this observation by investigating three problems. 1. Error-Erasure Decoding for Fixed-Length Block Codes with Feedback: Error-erasure codes with communication and control phases, introduced by Yamamoto and Itoh, are building blocks for optimal variable-length block codes. We improve their performance by changing the decoding scheme and tuning the durations of the phases, and establish inner bounds to the tradeoff between error exponent, erasure exponent and rate. We bound the loss of performance due to the encoding scheme of Yamamoto-Itoh from above by deriving outer bounds to the tradeoff between error exponent, erasure exponent and rate both with and without feedback. We also consider the zero error codes with erasures and establish inner and outer bounds to the optimal erasure exponent of zero error codes. In addition we present a proof of the long known fact that, the error exponent tradeoff between two messages is not improved with feedback. 2. Unequal Error Protection for Variable-Length Block Codes with Feedback: We use Kudrayashov's idea of implicit confirmations and explicit rejections in the framework of unequal error protection to establish inner bounds to the achievable pairs of rate vectors and error exponent vectors. Then we derive an outer bound that matches the inner bound using a new bounding technique. As a result we characterize the region of achievable rate vector and error exponent vector pairs for bit-wise unequal error protection problem for variable-length block codes with feedback. Furthermore we consider the single message message-wise unequal error protection problem and determine an analytical expression for the missed detection exponent in terms of rate and error exponent, for variable-length block codes with feedback. 3. Feedback Encoding Schemes for Fixed-Length Block Codes: We modify the analysis technique of Gallager to bound the error probability of feedback encoding schemes. Using the encoding schemes suggested by Zigangirov, D'yachkov and Burnashev we recover or improve all previously known lower bounds on the error exponents of fixedlength block codes.by Bariş Nakiboḡlu.Ph.D

Factors Affecting the General Academic Achievement of University Students: Gender, Study Hours, Academic Motivation, Metacognition and Self-Regulated Learning

This study aimed to determine the effects of university students\u27 gender, weekly study hours, academic motivation, metacognition, and self-regulated learning levels on their overall academic achievement and to examine whether academic motivation, metacognition and self-regulated learning total scores predicted their GPAs. This study utilized a survey and prediction research design to analyze the research questions posed. The participants of the study consisted of 86 undergraduate students attending various programs of a university in Western Canada. The research data were collected using the “Metacognitive Awareness Inventory (MAI)” developed by Schraw and Dennison (1994), the “Self-regulated learning perception scale (SASR)” developed by Dugan and Andrade (2011), the Academic Motivation Scale (AMS-C 28) College Version developed by Vallerand, Pelletier, Blais, Brière, Senécal and Vallières (1992), and the “demographic form”. We found a significant relationship between the university students\u27 self-regulated learning, metacognition and academic motivation scores, and their grade point averages (GPAs). We also determined that the total scores related to the university students’ self-regulated learning, metacognition and academic motivation significantly predicted their GPAs, and that the gender and weekly study hours of the university students did not have a significant effect on their self-regulated learning, metacognition, academic motivation and academic GPA

Conscious Reasoning or Quick Intuition?

This essay raises some methodological objections towards the theories of judgment and action in Haidt and Wegner, challenging the validity of their claim that the experience of free will is deceptive and results from the operation of an unconscious and automatic mechanism of judgment. The main thrust of the argument is that the mechanism used to explain moral judgment as well as the experience of free will is impossible to falsify and untestable. A brief comparison with the argument for the direct relationship between moral choice and free will in Kant aims to show that the mentioned psychological accounts have ignored the normative nature of moral decision making at their own expense, and explain too much only by overlooking the distinct experience of judging

21. YÜZYILDA DEMOKRASİ VE EKONOMİK BÜYÜME İLİŞKİSİ: BİR LİTERATÜR İNCELEMESİ

Demokrasi ve ekonomik performans arasındaki ilişkiler sosyal bilimciler özellikle de ekonomistleri son birkaç yüzyıldır ilgilendiren konulardandır. Ancak son dönemlerde özellikle Orta Doğu’da yaşanan demokratikleşme hareketleri, demokrasi ile ekonomik büyüme arasındaki ilişkinin yeniden gündeme gelmesine neden olmuştur. Bu çalışma ile demokrasi ile gelişme-büyüme arasındaki ilişkiyi inceleyen farklı görüşleri sunarak, iki kavram arasındaki ilişkinin daha belirgin hale getirilmesine katkı sağlamak ve özellikle ampirik çalışmalar ışığında 21. yüzyılda bu ilişkinin nasıl olduğunu (varlığı/yokluğu, yönü, derecesi) irdelemek amaçlanmıştır. Yapılan kuramsal ve ampirik değerlendirmede, genel anlamıyla ekonomik büyüme açısından demokratik kurumların daha elverişli (olumlu) olduğu söylenebilir. Bu sonuç, demokrasi ile ekonomik büyüme arasında pozitif ilişki olduğunu ifade eden Bağdaşma Yaklaşımını desteklemektedir. Türkiye’de demokrasi-ekonomik büyüme ilişkisini araştıran az sayıda çalışma incelendiğinde, uluslararası literatürdeki her üç görüşe uygun sonuçların elde edildiği görülmüştür

Pravilni poligoni u taxicab ravnini

In this paper, we define taxicab regular polygons and determine which Euclidean regular polygons are also taxicab regular, and which are not. Finally, we investigate the existence or nonexistence of taxicab regular polygons.U radu definiramo pravilne taxicab poligone i određujemo koji su pravilni euklidski poligoni ujedno i pravilni taxicab poligoni, a koji nisu. Naposljetku, ispitujemo postojanje ili nepostojanje pravilnih taxicab poligona

Fundraising and Optimal Policy Rules

This paper develops a simple spatial model of fundraising, in which charities select a target population to solicit donations. First, we show that in a competitive charity market without any intervention, the number of charities in the market and/or the overall net funds raised by charities may be sub-optimal. Next, we analyze whether a social planner can prevent such shortcomings and show that a regulatory mechanism can be designed to achieve socially desirable outcomes. In contrast to the previous literature, our model does not necessarily produce monopoly as the optimal market structure. We show that if fixed costs associated with establishing charities are sufficiently low, then the optimal market structure is not a monopoly. Given the importance of the trade-o¤ between the volume and variety of charitable services, we argue that this result may be of particular interest to policy makers

Variable block length coding for channels with feedback and cost constraints

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 95-96).Variable-decoding-time/generalized block-coding schemes are investigated for discrete memoryless channels (DMC) with perfect feedback (error free, delay free, infinite capacity) under cost constraints. For a given number of messages and average error probability, upper and lower bounds are found for expected decoding time. These coincide with each other up to a proportionality constant which approaches one in a certain asymptotic sense. A resulting reliability function is found for variable decoding time DMC's with perfect feedback under a cost constraint. The results in this work generalize Burnashev's results, to the cost constrained case.by Bariş Nakiboḡlu.S.M

WORKERS AVOIDANCE OF USING THEIR RIGHTS: THE CAUSES

Çalışma yaşamını düzenleyen mevzuat sayesinde, işçiler çok sayıda yasal hakka sahip bulunmaktadır. Fakat işçilere çeşitli haklar tanınması, bunlardan mutlaka yararlandıklarını göstermemektedir. Hukuki yaptırımlara karşın, işçiler haklarını kullanmaktan kaçınabilmektedir. Çünkü hakların işçilerin öznel değerlendirmeleri ile şekillenen bir boyutu bulunmaktadır. İşçiler haklarını kullanma konusunda bir maliyet/kazanç değerlendirmesi yapmaktadır. İşçilerin hakları kullanma konusundaki değerlendirmeleri kişilik özellikleri, iş ve işveren ile ilgili faktörler ve işsizlik ile iş güvencesizliği gibi faktörlerden etkilenmektedir. Çalışmanın amacı, işçilerin haklarını kullanma sürecini ve bu süreci etkileyen faktörleri açıklamaktır. Çalışmada işçilerin haklarını kullanmalarını sağlayabilecek işçi sendikaları, işyeri kurulları gibi kurumlara da değinilenecektir. Ayrıca ayrımcılık ve iş güvencesi düzenlemeleri ile sosyal sorumluluk uygulamaları da bu açıdan ele alınmaktadır. Through the legislation which regulates the working life, workers have a lot of statutory rights. But it doesn't mean that the workers exercises this rights certainly. In spite of the legal sanctions, workers can avoid to exercise their rights. Because rights have a dimension which shaped by the worker's subjective consideration. Workers make an cost/benefit assessment about exercising rights. These assessments affected by some factors such as personality characteristics, job and employer related factors, unemployment and job insecurity. The main aim of this study is explaining the process of exercising rights of workers and the factors which affects these process. In this study, trade unions and workplace committees which can provide the exercising these rights are discussed. On the other hand, discrimination and employment security regulations, and social responsibility practices are also addressed