Computer Engineering Commons^™

การควบคุมคุณภาพการให้บริการโดยใช้แผนราคาในโครงข่ายเข้าถึง, ธนชาติ วีระพันธุ์

Chulalongkorn University Theses and Dissertations (Chula ETD)

ปัจจุบันเทคโนโลยีการสื่อสารทั้งมีสายและไร้สายได้พัฒนาไปอย่างรวดเร็ว ประกอบกับความต้องการที่จะใช้บริการเทคโนโลยีการสื่อสารที่มากขึ้นอย่างต่อเนื่อง แต่ด้วยทรัพยากรที่มีอยู่อย่างจำกัด จึงทำให้เกิดความคับคั่งในระบบโครงข่ายเข้าถึง จึงเป็นสาเหตุทำให้โครงข่ายเกิดการประวิงและยากต่อการควบคุมคุณภาพการให้บริการ เพื่อแก้ปัญหาดังกล่าวจึงนำแผนราคาเข้ามาจูงใจในการเข้าใช้บริการ ในโครงข่าย ในวิทยานิพนธ์ฉบับนี้จำลองระบบด้วยแถวคอย M/M/1 โดยแบ่งรูปแบบของแถวคอยออกเป็น แบบเดี่ยว และ แบบลำดับความสำคัญ โดยกรณีของแถวคอยแบบเดี่ยว เมื่อระบบเกิดความคับคั่ง ทำให้มีการปรับราคา ผู้ใช้บริการที่ไม่ยอมรับราคาที่เปลี่ยนไปจะไม่ได้เข้าสู่ระบบ ส่วนในกรณีของแถว คอยแบบลำดับความสำคัญ เมื่อระบบเกิดความคับคั่ง ทำให้มีการปรับราคา ผู้ใช้บริการที่ไม่ยอมรับ ราคาที่เปลี่ยนไปสามารถเข้าสู่ระบบได้แต่ต้องรอให้ผู้ใช้บริการที่ยอมรับราคาที่เปลี่ยนไปใช้บริการเสร็จ ก่อน นอกจากนั้น แถวคอยลำดับความสำคัญยังแบ่งออกเป็นสองกรณี กรณีแรกคือผู้ใช้บริการ ที่ยอมรับราคาที่เปลี่ยนไปสามารถขัดจังหวะการใช้บริการของผู้ใช้บริการที่ไม่ยอมรับราคาที่เปลี่ยนไป ได้ทันที กรณีที่สองคือผู้ใช้บริการที่ยอมรับราคาที่เปลี่ยนไปต้องรอให้ผู้ใช้บริการที่ไม่ยอมรับราคาที่ เปลี่ยนไปใช้บริการเสร็จก่อน วิทยานิพนธ์ฉบับนี้เสนอการวิเคราะห์ทางคณิตศาสตร์และการจำลองระบบทางคอมพิวเตอร์เพื่อหาค่าที่เหมาะสมของความน่าจะเป็นที่ผู้ใช้บริการจะยอมรับราคาที่ปรับขึ้น ราคาใหม่ที่ปรับขึ้นอย่าง เหมาะสม เวลาประวิงของแพ็กเกตเฉลี่ย เวลาเฉลี่ยที่แพ็กเกตอยู่ในระบบ ความน่าจะเป็นที่เวลา ประวิงของแพ็กเกดจะมีค่ามากกว่าเวลาประวิงของแพ็กเกตที่กำหนด และรายได้ที่คาดหวังเฉลี่ย โดยผลลัพธ์จากการวิเคราะห์ทางคณิตศาสตร์และการจำลองระบบทางคอมพิวเตอร์ที่นำแผนราคามา ประยุกต์ใช้กับรูปแบบของแถวคอยทั้งสองสามารถควบคุมคุณภาพการให้บริการได้ตามค่าที่กำหนด จากการศึกษาด้วยการวิเคราะห์และการจำลองระบบด้วยคอมพิวเตอร์ให้ผลลัพธ์ที่สอดคล้องกัน

An Intelligent System For High Resolution Radar Systems, Janette C. Briones

Open Access Theses & Dissertations

Cognitive radio is a recent, novel approach that integrates machine perception software into wireless systems. The term cognitive radio was first used by Joe Mitola. The concept and the term cognitive radio quickly caught the attention and interest of many in the communications field. Cognitive radios are capable of making decisions and selecting or modifying the operating parameters of a radio. Given these capabilities, it is feasible to build a cognitive radar system as introduced by Simon Haykin in 2006. Cognitive radar, as described by Haykin, is an intelligent system that must be aware of its environment, uses prior knowledge, …

Multi-Objective Border Patrolling Optimization Using Game Theory And Evolutionary Algorithms, Franciso Oswaldo Aguirre

Open Access Theses & Dissertations

Border security has evolved significantly since the days when no more than 75 Mounted Guards patrolled the U.S. border in the early 1900's. The border region includes thousands of miles of both land and maritime borders that must be controlled, as well as commercial transportation networks. One of the primary components of the Department of Homeland Security (DHS) is the U.S. Customs and Border Protection (CBP) agency. One of the most typical activities performed by CBP is patrolling the expansive open areas in between official points of entry (POEs) to prohibit illegal entry attempts. Roving patrols are routinely conducted by …

Numerical Investigation Of Impact Of Relative Humidity On Droplet Accumulation And Film Cooling, Luz Irene Bugarin

Open Access Theses & Dissertations

During the summer, high inlet temperatures affect the power output of gas turbine systems. Evaporative coolers have gained popularity as an inlet cooling method for these systems. Wet compression has been one of the common evaporative cooling methods implemented to increase power output of gas turbine systems due to its simple installation and low cost. This process involves injection of water droplets into the continuous phase of compressor to reduce the temperature of the flow entering the compressor and in turn increase the power output of the whole gas turbine system. This study focused on a single stage rotor-stator compressor …

Implementing Mechatronics Design Methodology In Mechanical Engineering Technology Senior Design Projects At The Old Dominion University, Vukica M. Jovanovic, Jennifer G. Michaeli, Otilia Popescu, Moustafa R. Moustafa, Mileta Tomovic, Alok K. Verma, Cheng Y. Lin

Engineering Technology Faculty Publications

In recent years, the nature of engineering design has changed due to advances in embedded system design and computer technologies. It is rare to engineer a purely mechanical design that does not incorporate electrical and electronic components. Mechanical engineers and mechanical engineering technologists must possess a multi-disciplinary knowledge with the understanding of both mechanical and electrical systems. For this purpose, undergraduate programs in engineering technology have added mechatronics courses to their curriculum. Mechatronics is a design process that is multi-disciplinary in nature and integrates principles of many engineering disciplines including, but not limited to, mechanical engineering, electrical engineering, and controls …

Cross-Domain Password-Based Authenticated Key Exchange Revisited, Liqun Chen, Hoon Wei Lim, Guomin Yang

Research Collection School Of Computing and Information Systems

We revisit the problem of secure cross-domain communication between two users belonging to different security domains within an open and distributed environment. Existing approaches presuppose that either the users are in possession of public key certificates issued by a trusted certificate authority (CA), or the associated domain authentication servers share a long-term secret key. In this article, we propose a generic framework for designing four-party password-based authenticated key exchange (4PAKE) protocols. Our framework takes a different approach from previous work. The users are not required to have public key certificates, but they simply reuse their login passwords, which they share …

On The Security Of Auditing Mechanisms For Secure Cloud Storage, Yong Yu, Lei Niu, Guomin Yang, Yi Mu, Willy Susilo

Research Collection School Of Computing and Information Systems

Cloud computing is a novel computing model that enables convenient and on-demand access to a shared pool of configurable computing resources. Auditing services are highly essential to make sure that the data is correctly hosted in the cloud. In this paper, we investigate the active adversary attacks in three auditing mechanisms for shared data in the cloud, including two identity privacy-preserving auditing mechanisms called Oruta and Knox, and a distributed storage integrity auditing mechanism.We show that these schemes become insecure when active adversaries are involved in the cloud storage. Specifically, an active adversary can arbitrarily alter the cloud data without …

Measuring And Modelling The Thermal Performance Of The Tamar Suspension Bridge Using A Wireless Sensor Network, Nicholas De Battista, James M. W. Brownjohn, Hwee-Pink Tan, Ki Young Koo

Research Collection School Of Computing and Information Systems

A study on the thermal performance of the Tamar Suspension Bridge deck in Plymouth, UK, is presented in this paper. Ambient air, suspension cable, deck and truss temperatures were acquired using a wired sensor system. Deck extension data were acquired using a two-hop wireless sensor network. Empirical models relating the deck extension to various combinations of temperatures were derived and compared. The most accurate model, which used all the four temperature variables, predicted the deck extension with an accuracy of 99.4%. Time delays ranging from 10 to 66 min were identified between the daily cycles of the air temperature and …

Detection And Control Of Small Civilian Uavs, Matthew Peacock

Theses : Honours

With the increasing proliferation of small civilian Unmanned Aerial Vehicles (UAVs), the threat to critical infrastructure (CI) security and privacy is now widely recognised and must be addressed. These devices are easily available at a low cost, with their usage largely unrestricted allowing users to have no accountability. Further, current implementations of UAVs have little to no security measures applied to their control interfaces. To combat the threat raised by small UAVs, being aware of their presence is required, a task that can be challenging and often requires customised hardware.

This thesis aimed to address the threats posed by the …

An Analysis Of Use Of Automated Tools For Improving The Process Of Software Verification And Validation In A Midwestern Company, Darshak Dodiya

Dissertations and Theses @ UNI

As the use of electronics and software in the modern off road vehicles tend to increase, there is a huge challenge of getting the electronics and software tested before making it available for customer use. There are a lot of interactions between the hardware and software for the vehicle to function. And with the amount of interactions in the hardware and software come a lot of problems in verifying the functionality of the vehicle. If proper verification is neglected, the customer might end up getting an unsafe vehicle which can lead to serious consequences. To make these vehicles safe and …

Non-Local Model For The Spatial Distribution Of Impact Ionization Events In Avalanche Photodiodes, David A. Ramirez, Majeed M. Hayat, Andrew S. Huntington, George M. Williams

Electrical and Computer Engineering Faculty Research and Publications

We report an extension of the analytical dead space multiplication theory that provides the means to theoretically determine the spatial distribution of electron and hole impact-ionization events in an arbitrarily specified heterojunction multiplication region. The model can be used to understand the role of the dead space in regularizing the locations of impact ionization. It can also be utilized to analyze, design, and optimize new generations of ultra-low noise, multistaged gain avalanche photodiodes based upon judiciously energizing and relaxing carriers to enhance electron impact ionization and suppress hole impact ionization.

Graduate School Of Computer And Information Sciences Viewbook, Nova Southeastern University

College of Engineering and Computing Course Catalogs

No abstract provided.

Fabrication And Application Of A Polymer Neuromorphic Circuitry Based On Polymer Memristive Devices And Polymer Transistors, Robert A. Nawrocki

Electronic Theses and Dissertations

Neuromorphic engineering is a discipline that aims to address the shortcomings of today's serial computers, namely large power consumption, susceptibility to physical damage, as well as the need for explicit programming, by applying biologically-inspired principles to develop neural systems with applications such as machine learning and perception, autonomous robotics and generic artificial intelligence.

This doctoral dissertation presents work performed fabricating a previously developed type of polymer neuromorphic architecture, termed Polymer Neuromorphic Circuitry (PNC), inspired by the McCulloch-Pitts model of an artificial neuron. The major contribution of this dissertation is a development of processing techniques necessary to realize the Polymer Neuromorphic …

Lightweight Data Compression In Wireless Sensor Networks Using Huffman Coding, Henry P. Medeiros, Marcos C. Maciel, Richard D. Souza, Marcelo E. Pellenz

Electrical and Computer Engineering Faculty Research and Publications

This paper presents a lightweight data compression method for wireless sensor networks monitoring environmental parameters with low resolution sensors. Instead of attempting to devise novel ad hoc algorithms, we show that, given general knowledge of the parameters that must be monitored, it is possible to efficiently employ conventional Huffman coding to represent the same parameter when measured at different locations and time periods. When the data collected by the sensor nodes consists of integer measurements, the Huffman dictionary computed using statistics inferred from public datasets often approaches the entropy of the data. Results using temperature and relative humidity measurements show …

Robust And Resilient State-Dependent Control Of Continuous-Time Nonlinear Systems With General Performance Criteria, Xin Wang, Edwin E. Yaz, James Long

Electrical and Computer Engineering Faculty Research and Publications

A novel state-dependent control approach for continuous-time nonlinear systems with general performance criteria is presented in this paper. This controller is optimally robust for model uncertainties and resilient against control feedback gain perturbations in achieving general performance criteria to secure quadratic optimality with inherent asymptotic stability property together with quadratic dissipative type of disturbance reduction. For the system model, unstructured uncertainty description is assumed, which incorporates commonly used types of uncertainties, such as norm-bounded and positive real uncertainties as special cases. By solving a state-dependent linear matrix inequality at each time, sufficient condition for the control solution can be found …

Thermal Tuning Of Mems Buckled Membrane Actuator Stiffness, Robert A. Lake, Kyle K. Ziegler, Ronald A. Coutu Jr.

Electrical and Computer Engineering Faculty Research and Publications

The thermal tuning characteristics of a microelectromechanical systems (MEMS) buckled membrane exhibiting regions of both positive and negative stiffness is examined and analyzed using finite element method (FEM) simulation and through experimentation. The membranes are fabricated by releasing a silicon/silicon dioxide (Si/SiO₂) laminated membrane from a silicon on insulator (SOI) wafer. The difference in thermal expansion coefficients between Si and SiO2 induces a compressive stress in the SiO₂ layer causing out-of-plane buckling of the membrane. This structure is found to have positive and negative stiffness regions when actuated with a transverse force. It is demonstrated that the …