Neuro-fuzzy controller in real-time feedback schedulers

Traditional scheduling algorithms worked on closed and highly predictable environments. However present day systems need to work in more open and unpredictable environments; such as mobile robots, on-line trading, e-commerce, multimedia that cannot be driven well with traditional open-loop algorithms. A new scheduling paradigm, feedback control scheduling, therefore has been presented recently to fulfil the requirements of such systems. This algorithm defines error terms for schedules, monitors the error, and continuously adjusts the schedule to maintain stable performance. When PID (Proportional-Integral-Derivative) controller is used to control the CPU utilization, one of the problems faced is that when utilization setpoint is closer to 100%, in severely overloaded conditions, systems can have a longer settling time than the analysis based on the linear model since utilization feedback saturates at 100%. To overcome this problem, a neuro-fuzzy controller is designed instead of PID. Simulations showed that settling time with the neuro-fuzzy controller is approximately four times shorter than the one with the PID controller

A new embedded controller for data acquisition and control applications

Developing high performance data acquisition and control systems takes better tools than the industry normally provides. As the most common controllers, PLCs can be still weak in many applications, and especially they are not good choice for data acquisition due to their limited capability of computation, speed, memory and programming constraints. The fact that today s PCs have many advantages compared with their relatively low price made them very popular in industrial environments. In this project a PC based controller was designed for data acquisition and control purposes. Although such similar systems exist, this product with some advantages could be a good alternative to the existing ones

Coefficient-based exact approach for frequent itemset hiding

Concealing sensitive relationships before sharing a database is of utmost importance in many circumstances. This implies to hide the frequent itemsets corresponding to sensitive association rules by removing some items of the database. Research efforts generally aim at finding out more effectivemethods in terms of convenience, execution time and side-effect. This paper presents a practical approach for hiding sensitive patterns while allowing as much nonsensitive patterns as possible in the sanitized database. We model the itemset hiding problem as integer programming whereas the objective coefficients allow finding out a solution with minimum loss of nonsensitive itemsets. We evaluate our method using three real datasets and compared the results with a previous work. The results show that information loss is dramatically minimized without sacrificing the accuracy

Transforming VHDL to timed automata

Technical Report No: IYTE-COMPENG-2015-001This report presents the transformation of behavioral VHDL programs to Timed Automata

Stability properties of adaptive real-time feedback scheduling: A statistical approach

This paper focuses on the statistical analysis of an adaptive real-time feedback scheduling technique based on imprecise computation. We consider two-version tasks made of a mandatory and an optional part to be scheduled according to a feedback control rate-monotonic algorithm. A Proportional-Integral-Derivative (PID) control action provides the feedback strategy for deciding about the execution or rejection of the optional sub-tasks. By modelling the task execution times as random variables, we compute the probability density of the CPU utilization and derive conditions on PID parameters guaranteeing the stability of the overall system around a desired level of CPU utilization. This allows us to highlight the tasks statistics and the scheduling parameters that affect critically stability. The analysis is developed by first exploiting a number of simplifying assumptions that are progressively removed. The main results are also demonstrated through monte-carlo simulations of the scheduling algorithm.Izmir Institute of Technology and Institute Ae´ronautique et Spatia

Fourier analysis-based testing of finite state machines

12th Turkish National Software Engineering Symposium, UYMS 2018; Istanbul; Turkey; 10 September 2018 through 12 September 2018Sonlu durum makinesi (FSM), devre ve yazılım testlerinde yaygın kullanıma sahip bir modelleme tekniğidir. FSM'lerin testi için literatürde çeşitli yöntemler bulunmakla birlikte, modellerin büyümesi sonucu test kümesinin büyüklüğü, hata yakalama oranı ve test üretim süresi gibi konularda yüksek başarıma sahip alternatif test yöntemlerine ihtiyaç bulunmaktadır. Bu çalışma ikili fonksiyonların Fourier analizine dayanan yeni bir test oluşturma yöntemi önermektedir. İlk sonuçlar, fonksiyonun frekans bileşenlerinden yararlanarak oluşturulan test takımının daha yüksek bir performansa sahip olduğunu göstermektedir. Önerilen yöntem, karakteristiği, maliyeti ve hata yakalama oranı üzerinden literatürden seçilen iki yöntemle karşılaştırılmıştır.Finite State Machine (FSM), as a formal modeling technique to represent both circuits and software, has been widely used in testing. FSM testing is a well-studied subject and there are several test generation methods. However, the current increase in the demand for pervasive and safety critical systems as well as the increase in software size calls for more rigorous methods that can produce more effective test suites particularly in terms of size, time spent for test generation and fault detection ratio. In this study, we propose a new test generation method based on the Fourier analysis of Boolean functions. An analysis on the effects of the various frequency components of the function output allow us to generate test suites with better performance characteristics. We compare our F-method with the two existing methods

Implementation of Real-Time Adaptive Scheduling Technique on RT-Linux

Bu çalışma kesinleşmemiş hesaplamalar yöntemine dayalı olan gerçek-zamanlı geribesleme denetimli bir görev planlama tekniğinin ("Real Time Feedback Control Scheduling") Gerçek zamanlı Linux (Rt-Linux) üzerindeki uygulamasını sunmaktadır. Zorunlu ve seçmeli alt-görevlerden oluşan ve geribesleme denetimli "rate-monotonic" tekniğine göre planlanan iki-sürümlü görev modeli seçilmiştir. Oransal-Entegral-Türev (PID) denetim, seçmeli alt görevlerin çalıştırılması veya reddedilmesinde gerekli geribesleme stratejisini sağlamak için kullanılmıştır. Oluşturulan bu model RT-Linux işletim sistemine uygulanmış ve sistem başarımı yapay bir iş yükü altında sınanarak önerilen görev planlama modelinini sistemi öngörülen A/B kullanım oranı düzeyinde kararlı halde çalışabildiği gösterilmiştir.This paper presents an RT-Linux implementation of real-time feedback control scheduling technique based on imprecise computations. We consider twoversion tasks: one defined as mandatory and the other defined as optional for scheduling according to a feedback control rate-monotonic algorithm. A Proportional-Integral-Derivative (PID) control action provides the feedback strategy for deciding on the execution or rejection of the optional sub-tasks. The proposed model is implemented and evaluated on RT-Linux. The experimental results show that the proposed model can successfully keep the system stable at a desired level of CPU utilization

FPGA ile gerçeklenen devrelerde hataya dayanıklılık

Hataya dayanıklılık (Fault-Tolerance) özellikle güvenliğin önemli olduğu kritik uygulamalarda ve kontrol sistemlerinde büyük önem taşımaktadır. Bu çalışmada FPGA ile gerçeklenen devrelerin otomatik olarak aksaklığa dayanıklı hale dönüştürülmesi için geliştirilen bir teknik sunulmaktadır. VHDL dilinde yazılmış olan devre kodu, göreceli kısa bir dönüşüm betiği ile otomatik olarak hataya dayanıklı hale getirilmektedir. Önerilen metot, FPGA üzerinde gerçeklenmiş bir sonsuz darbe cevaplı (IIR) süzgeç ile sınanarak benzetim sonuçları verilmekte, kullanılan tekniğin basitliği ve buna karşın önemi ve etkinliği sunulmaktadır

Acute mesenteric venous thrombosis: Case for nonoperative management

AbstractObjective: Initial treatment in the management of acute mesenteric vein thrombosis (MVT) is controversial. Some authors have proposed a surgical approach, whereas others have advocated medical therapy (anticoagulation). In this study, we analyzed and compared the results obtained with surgical and medical treatment to determine the best initial management for this disease. Methods: We retrospectively reviewed the records of patients treated for MVT in a secondary care surgical department from January 1987 to December 1999. Before January 1995, our departmental policy was to perform surgery in patients with suspected MVT. Since January 1995, we have preferred a medical approach when achievable. Each patient in this study was assessed for diagnosis, initial management (laparotomy or anticoagulation), morbidity, mortality, duration of hospitalization, the need for secondary operation, portal hypertension, and survival rates. Results: Twenty-six patients were treated, 14 before January 1995 (group 1) and 12 since January 1995 (group 2). Morbidity, mortality, secondary operation, portal hypertension, and 2-year survival rates were 34.6%, 19.2%, 15.3%, 19.2%, and 76.9%, respectively. No statistical difference was observed between the two groups. The mean duration of hospitalization was 51.6 days in group 1 and 23.2 days in group 2 (P <.05). Among the 12 patients treated by means of laparotomy with bowel resection, 10 patients (83%) had mucosal necrosis without transmural necrosis at pathologic study. Conclusion: Nonoperative management for acute MVT is feasible when the initial diagnosis with a computed tomography scan is certain and when the bowel infarction has not led to transmural necrosis and bowel perforation. The morbidity, mortality, and survival rates are similar in cases of surgical and nonoperative management. The length of hospital stay is shorter when patients are treated with a nonoperative approach. A nonoperative approach, when indicated, avoids the resection of macroscopically infarcted small bowel (without transmural necrosis) in cases that are potentially reversible with anticoagulation alone. (J Vasc Surg 2001;34:673-9.

Bir ağ yönetim sistemi: GuardiLAN

Bilgisayar ağlarındaki hızlı gelişime rağmen ağ yönetim sistemleri bu gelişimin gerisinde kalmaktadır. Ağların hızla gelişmesi, ağda oluşan trafik tiplerindeki çeşitlilik, ve kaynaklardaki kısıtlılık Servis Kalitesi ve Network Yönetimi konularını daha önemli hale getirmiştir. Bu bildiride, İzmir Yüksek Teknoloji Enstitüsü’nün yerel bilgisayar ağı için geliştirilen GuardiLAN projesi sunulacaktır. GuardiLAN ilk aşamada 3 kısımdan oluşan, modüler ve web tabanlı bir ağ yönetim sistemidir. Birinci kısım ağ topolojisinin belirlenmesinden ve takibinden sorumlu olup, ikinci kısım kullanıcıların IP adreslerinin ve MAC adreslerinin düzenli olarak kontrolüyle ağ güvenliğinin yükseltilmesini sağlamaktadır. Son kısım ise geniş alan ağı bağlantısının etkin kullanımı için geliştirilmiş bir akıllı bant genişliği yönetim aracıdır