PERFORMABILITY EVALUATION OF FAULT-TOLERANT COMPUTER SYSTEMS USING DYQNTOOL+

1995 ◽  
Vol 02 (04) ◽  
pp. 383-404 ◽  
Author(s):  
BOUDEWIJN R. HAVERKORT
Keyword(s):  
Fault Tolerant ◽  
Computer Systems ◽  
Stochastic Petri Nets ◽  
System Behavior ◽  
Queuing Network ◽  
Evaluation Tool ◽  
Network Concept ◽  
And Performance ◽  
Mutual Relations

For fault-tolerant computer systems (FTCS) supporting critical applications, it is of key importance to be able to answer the question of whether they indeed fulfill the quality of service requirements of their users. In particular, answers related to the combined performance and dependability of the FTCS are important. To facilitate these so-called performability studies, we present DYQNTOOL+, a performability evaluation tool based on the dynamic queuing network concept, that allows for a combined modeling of system performance and dependability. Different from other performability evaluation tools, DYQNTOOL+ combines two different modeling paradigms, i.e., queuing networks and stochastic Petri nets, for respectively the performance and the dependability aspects of the system under study. The mutual relations between these two model parts, such as workload-induced failures and performance decreases due to failures, are explicitly modeled as well. By the above choice for such a combination of modeling paradigms, the modeling can be done in greater detail, thereby often revealing system behavior that cannot be revealed otherwise. We present the dynamic queuing network modeling approach and its implementation in DYQNTOOL+, as well as illustrate its usage by addressing a number of examples.

Searching for majority with k-tuple queries

2015 ◽  
Vol 07 (02) ◽  
pp. 1550009 ◽  
Author(s):  
Gianluca De Marco ◽  
Evangelos Kranakis
Keyword(s):  
Computer System ◽  
Fault Tolerant ◽  
Computer Systems ◽  
Limited Resources ◽  
Number Of Components ◽  
Diagnostic Property

Diagnosing the quality of components in fault-tolerant computer systems often requires numerous tests with limited resources. It is usually the case that repeated tests on a selected, limited number of components are performed and the results are taken into account so as to infer a diagnostic property of the computer system as a whole. In this paper we abstract fault-tolerant testing as the following problem concerning the color of the majority in a set of colored balls. Given a set of balls each colored with one of two colors, the majority problem is to determine whether or not there is a majority in one of the two colors. In case there is such a majority, the aim is to output a ball of the majority color, otherwise to declare that there is no majority. We propose algorithms for solving the majority problem by repeatedly testing only k-tuple queries. Namely, successive answers of an oracle (which accepts as input only k-tuples) to a sequence of k-tuple queries are assembled so as to determine whether or not the majority problem has a solution. An issue is to design an algorithm which minimizes the number of k-tuple queries needed in order to solve the majority problem on any possible input of n balls. In this paper we consider three querying models: Output, Counting, and General, reflecting the amount and type of information provided by the oracle on each test for a k-tuple.

scholarly journals Mastering Uncertain Operating Conditions in the Development of Complex Machine Elements by Validation Under Dynamic Superimposed Operating Conditions

2021 ◽  
pp. 236-251
Author(s):  
Thiemo Germann ◽  
Daniel M. Martin ◽  
Christian Kubik ◽  
Peter Groche
Keyword(s):  
Operating Conditions ◽  
Evaluation Tool ◽  
Complex Interactions ◽  
Machine Element ◽  
Operating Load ◽  
Machine Elements ◽  
And Performance ◽  
Investment Goods ◽  
Further Development

AbstractMachine elements produced in large quantities undergo several development cycles and can be adapted from generation to generation. Thus, experiences from real operation can be taken into account in further development. This is not possible for innovative investment goods such as special purpose machines, as these are usually individual items. Therefore, functionality and quality of newly developed components must be assured by previous investigations.Conventional methods are inadequate at this point, as they cannot represent the actual, complex operating conditions in the later application. A reliable statement about the behavior of the system through a comprehensive validation in laboratory tests under standardized conditions is not achievable in this way due to a multitude of diversified load cases.In previous work, a method was developed to allow testing of machine elements in the laboratory under detuned operating conditions. For this purpose, disturbance variables are applied to the system using paraffin wax phase change actuators in order to simulate real operation states and to analyze the behavior of the machine element under these conditions. The investigated disturbance variables are fluctuations and asymmetries of the operating load through superimposed temperature gradients. Complex interactions between the machine element and the adjacent components or the overall system can thus be taken into account.The functionality of the methodology has been developed and briefly demonstrated so far. This paper presents the next level within the development process of the methodology. The necessary components are explained in detail and an AI black box evaluation tool is discussed. This work is based on a test bench that applies dynamically changing states of detuning under superimposed disturbances. Additionally, energy efficiency and performance of the test setup is advanced. As presented, the method opens up the possibility of validating new machine elements in the laboratory under realistic conditions.

scholarly journals Performance Contract and Performance Evaluation of State-Owned Enterprises: Insights from the Goal Setting Theory

2013 ◽  
Vol 3 (2) ◽  
pp. 22 ◽  
Author(s):  
Samuel Nana Yaw Simpson
Keyword(s):  
Performance Evaluation ◽  
Goal Setting ◽  
Performance Studies ◽  
Evaluation Tool ◽  
Goal Setting Theory ◽  
Desirable Outcome ◽  
Setting Theory ◽  
And Performance ◽  
Theory Element

Performance contract (PC) is one of the initiatives under the impulse of reforming State-Owned Enterprises (SOEs) to among other things, ensure improved SOE performance. Studies however show mixed results in relation to improved SOE performance, and the general perception is that targets in PCs are not challenging enough. Drawing on the goal setting theory, this article provides further theoretical explanations for the application and impact of PCs using evidence from Ghana, the first Anglophone nation in Africa to adopt and implement the PC reform programmes. Relying primarily on data from PCs, SOE evaluation reports, and interviews, findings suggest that the quality of targets in PCs has been improving over the years. Moreover, the goal setting theory element, commitment, is crucial to achieving desirable outcome from PC as a performance evaluation tool.

LIGHTING AND PERFORMANCE: AN ANALYSIS ON LIGHTING EFFICIENCY OF ARCHITECTURE STUDIO

2019 ◽  
Vol 1 (1) ◽  
pp. 92
Author(s):  
Fazidah Hanim Husain
Keyword(s):  
Learning Environment ◽  
Comfort Level ◽  
Artificial Lighting ◽  
Level Measurement ◽  
Acceptable Range ◽  
Creative Learning ◽  
Illuminance Level ◽  
And Performance ◽  
Effect Of Light

Lighting is one of the key elements in any space and building infrastructure. Good design for an area in the building requires sufficient light that contributes to the efficiency of the activities. The correct method allows natural light to transmit, reduce heat and glare in providing a conducive learning environment. Light plays a significant influence to the quality of space and contributes focus of the students in an architecture studio. Previous research has shown that the effect of light also controlled emotions, behavior, and mood of the students. The operations of artificial lighting that have been used most of the time in an architecture studio during day and night may create lavishness and inadequacy at the same time. Therefore, this paper focuses on the identifying the quality of light for the architecture studio in UiTM (Perak), to instill a creative learning environment. Several methodologies adopted in this study such as illuminance level measurement using lux meter (LM-8100), and a questionnaire survey in gauging the lighting comfort level from students’ perspective. The study revealed that the illuminance level in the architecture studio is insufficient and not in the acceptable range stated in the Malaysian: Standards 1525:2007 and  not evenly distributed.  The study also concluded that the current studio environment is not condusive and appears monotonous. 

Strategic threats to energy security as risks of quality of people's life

2020 ◽  
Vol 16 (4) ◽  
pp. 730-744
Author(s):  
V.I. Loktionov
Keyword(s):  
Quality Of Life ◽  
Energy Security ◽  
Well Being ◽  
Scientific Methods ◽  
Analysis And Synthesis ◽  
General Scientific ◽  
And Performance ◽  
Economic Well Being ◽  
The Way

Subject. The article reviews the way strategic threats to energy security influence the quality of people's life. Objectives. The study unfolds the theory of analyzing strategic threats to energy security by covering the matter of quality of people's life. Methods. To analyze the way strategic threats to energy security spread across cross-sectoral commodity and production chains and influences quality of people's living, I applied the factor analysis and general scientific methods of analysis and synthesis. Results. I suggest interpreting strategic threats to energy security as risks of people's quality of life due to a reduction in the volume of energy supply. I identified mechanisms reflecting how the fuel and energy complex and its development influence the quality of people's life. The article sets out the method to assess such quality-of-life risks arising from strategic threats to energy security. Conclusions and Relevance. In the current geopolitical situation, strategic threats to energy security cause long-standing adverse consequences for the quality of people's life. If strategic threats to energy security are further construed as risk of quality of people's life, this will facilitate the preparation and performance of a more effective governmental policy on energy, which will subsequently raise the economic well-being of people.

The Determinants of Entrepreneurship Development in Spatial Systems

2017 ◽  
Vol 13 ◽  
pp. 8-24
Author(s):  
Zbigniew Zioło
Keyword(s):  
Spatial Scales ◽  
Institutional Barriers ◽  
Entrepreneurship Development ◽  
Continental Scale ◽  
Spatial Systems ◽  
Business Conditions ◽  
Mutual Relations ◽  
Growth Shape ◽  
Strategic Goal

The processes of technological  progress create new opportunities for economic, social and cultural growth, shape new relations between economic  entities and their environment,  and influence changes in the determinants  of entrepreneurship development.  These processes vary significantly in certain geographic locations, characterised by an enormous  diversity of natural, social, economic and cultural structures. As a consequence, this creates different opportunities  and different conditions for the development of entrepreneurship in certain spatial scales, from the continental scale, through national and regional to local scales. The article presents complex conditions  for the development of entrepreneurship, highlights its limitations resulting from institutional  barriers, and the importance of knowing the mechanisms of mutual relations between spatial systems and the influence of control instruments. The quality of central and local government authorities is of particular significance here, which do not always properly use the mechanisms of rational business support. A serious barrier to the development of entrepreneurship is the low quality of social capital, manifested in a lack of trust in institutional authorities and reluctance to engage in entrepreneurship and business development. The conclusions point out that further research should be developed that will take into account changing business conditions, with a defined strategic goal of raising the quality and standard of living, international competitiveness of the country and products in different market categories.

Return on Invesment (ROI) of Software Product: A Systematic Literature Review

2015 ◽  
Vol 6 (1) ◽  
pp. 50-57
Author(s):  
Rizqa Raaiqa Bintana ◽  
Putri Aisyiyah Rakhma Devi ◽  
Umi Laili Yuhana
Keyword(s):  
Return On Investment ◽  
Assessment Criteria ◽  
Software Product ◽  
And Performance ◽  
Rational Consideration ◽  
Actual Return ◽  
The Cost ◽  
Investment Models ◽  
The Impact

The quality of the software can be measured by its return on investment. Factors which may affect the return on investment (ROI) is the tangible factors (such as the cost) dan intangible factors (such as the impact of software to the users or stakeholder). The factor of the software itself are assessed through reviewing, testing, process audit, and performance of software. This paper discusses the consideration of return on investment (ROI) assessment criteria derived from the software and its users. These criteria indicate that the approach may support a rational consideration of all relevant criteria when evaluating software, and shows examples of actual return on investment models. Conducted an analysis of the assessment criteria that affect the return on investment if these criteria have a disproportionate effort that resulted in a return on investment of a software decreased. Index Terms - Assessment criteria, Quality assurance, Return on Investment, Software product

Analysis of Fault Tolerant Computer Systems.

1985 ◽  
Author(s):  
Ushio Sumita ◽  
J. G. Shanthikumar ◽  
Yasushi Masuda
Keyword(s):  
Fault Tolerant ◽  
Computer Systems

scholarly journals Manufacturing and development of a bolted GFRP flange joint for oil and gas applications

2021 ◽  
pp. 095440542198951
Author(s):  
Muhsin Aljuboury ◽  
Md Jahir Rizvi ◽  
Stephen Grove ◽  
Richard Cullen
Keyword(s):  
Pressure Vessel ◽  
Oil And Gas ◽  
Polyester Resin ◽  
High Strength ◽  
Adhesively Bonded ◽  
Acceptable Quality ◽  
Composite Pipe ◽  
And Performance ◽  
Composite Pipes

The goal of this experimental study is to manufacture a bolted GFRP flange connection for composite pipes with high strength and performance. A mould was designed and manufactured, which ensures the quality of the composite materials and controls its surface grade. Based on the ASME Boiler and Pressure Vessel Code, Section X, this GFRP flange was fabricated using biaxial glass fibre braid and polyester resin in a vacuum infusion process. In addition, many experiments were carried out using another mould made of glass to solve process-related issues. Moreover, an investigation was conducted to compare the drilling of the GFRP flange using two types of tools; an Erbauer diamond tile drill bit and a Brad & Spur K10 drill. Six GFRP flanges were manufactured to reach the final product with acceptable quality and performance. The flange was adhesively bonded to a composite pipe after chamfering the end of the pipe. Another type of commercially-available composite flange was used to close the other end of the pipe. Finally, blind flanges were used to close both ends, making the pressure vessel that will be tested under the range of the bolt load and internal pressure.

Sign in / Sign up

Export Citation Format

Share Document