An Empirical Study on Multicriteria Scheduling

This paper presents an empirical study of non-preemptive Multicriteria-Based, called MCB for short, scheduling policy. MCB scheduling policy uses multiple criteria of each request: arrival time, deadline, and processing time, to balance the requirements on both client and server sites. Weighted aggregation method is applied in this study to conduct the different measurements to a single figure of merit. For the empirical study, an M/G/1 queuing simulation system is implemented with MATLAB to represent a general server's incoming request scheduling system. Comparative simulation results of MCB with best effort scheduling policy on an overload situation show that MCB is an optimal scheduling policy

Presentation of consistent information from independent databases

This thesis addresses a particular aspect of the retrieval of information from a wide variety of global information sources. This aspect is based on the model of a user working on a topic of interest over an extended period of time. During the time period, information is accessed, assembled, and correlated to satisfy the user\u27s view of the topic. The objective of the research described in this thesis is to ensure that the information accessed by the user over the extended period of time is both complete and consistent from the user\u27s viewpoint. A fundamental problem is achieving such consistency is that the information sources, typically databases, or data files, are independently controlled with their own individual viewpoints. Changes in content, structure, and access can therefore be made without the direct knowledge of the user. In investigating this problem a number of current implementations of Heterogeneous Distributed Database Systems (HDDS) have been evaluated, including WAIS, ANSAware, and DATAPLEX. The mechanisms available in such systems do not address the requirements of the problem outlined in this thesis. A new set of mechanisms have been researched and implemented on a testbed as the central part of this thesis in order to match the requirements The core of this testbed is a workstation-based interface for the user termed the Computer Software Interface (CSI). The CSI has been implemented to demonstrate that the set of mechanisms proposed are viable. One major aspect of the CSI has been the design and development of a local working environment for the user, and the associated theoretical proof needed to demonstrate that successful and complete access of this environment may be performed. The thesis demonstrates, both theoretically and practically, how the user may be presented with consistent data from independent data sources over an extended time period

Intelligent Naming System: An Alternative for Enterprise Naming Management

People use “name ” in general to reference things easily. In addition, one name may refer to various types of things or objects (one name – many objects). For example, a convenience store named “Family Mart ” uses this single name for every branch. Similarly, names are also important in all computer communication. Name services have been developed to map logical names to physical resources. The structure of the current name services is hierarchical for scalability. However, this limits one name mapping to many objects. This paper proposes the new naming system called the Intelligent Naming System that employs the concept of sets and trees. The technique called One Name – Many Objects – One Result (ONMOOR) is proposed to ensure that the result of the mapping is the intended object. Furthermore, the proposed solution has been proved by theoretical analysis. 1

Automatic detection and correction of programming faults for software applications

Software reliability is an important feature of a good software implementation. However some faults which cause software unreliability are not detected during the development stages, and these faults create unexpected problems for users whenever they arise. At present most of the current techniques detect faults while a software is running. These techniques interrupt the software process when a fault occurs, and require some forms of restart. In this paper Precompiled Fault Detection (PFD) technique is proposed to detect and correct faults before a source code is compiled. The objective of the PFD technique is to increase software reliability without increasing the programmers' responsibilities. The concepts of ‘‘pre-compilation’’ and ‘‘pattern matching’’ are applied to PFD in order to reduce the risk of significant damage during execution period. This technique can completely eliminate the significant faults in a software and thus, improves software reliability

Blockchain-based privacy and security model for transactional data in large private networks

Abstract Cyberphysical systems connect physical devices and large private network environments in modern communication systems. A fundamental worry in the establishment of large private networks is mitigating the danger of transactional data privacy breaches caused by adversaries using a variety of exploitation techniques. This study presents a privacy-preserving architecture for ensuring the privacy and security of transaction data in large private networks. The proposed model employs digital certificates, RSA-based public key infrastructure, and the blockchain to address user transactional data privacy concerns. The model also guarantees that data in transit remains secure and unaltered and that its provenance remains authentic and secure during node-to-node interactions within a large private network. The proposed model has increased the encryption speed by about 17 times, while the decryption process is expedited by 4 times. Therefore, the average overall acceleration obtained was 16.5. Both the findings of the security analysis and the performance analysis demonstrate that the proposed model can safeguard transactional data during communications on large private networks more effectively and securely than the existing solutions

IPChain: Blockchain-Based Security Protocol for IoT Address Management Servers in Smart Homes

The dynamic host configuration protocol (DHCP) servers are forms of an Internet of Things (IoT) address management server (IoTAMS) that gives network configuration settings to newly connected hosts. Administrators of a network may save time by setting DHCP servers instead of every network node. However, the absence of a more robust authentication method for DHCP servers makes hosts susceptible to attacks since neither the server nor the users are able to check the other’s authenticity during DHCP connections. These concerns result in both internal and external threats to the system that have the potential to impair network services. Among these threats are malicious DHCP servers and DHCP starvation. This paper aims to provide a novel approach for tackling these issues and protect the DHCP protocol. The proposed model uses the Diffie–Hellman key exchange mechanism, the elliptic curve discrete logarithm problem (ECDLP), a one-way hash function, blockchain technology, and a smart contract. In addition, registration and validation processes provide support for the proposed model in combating DHCP risks for both internal and external system threats. Results from this study show that the proposed model has an average of 21.1% more resistance to a growing number of adversaries than the benchmark models, thus revealing that the model is better suited for the security of IoT address management servers in smart homes, thereby enhancing resilience against related threats and the success of IP address management

An Unbound Network Coding for Extended IEEE 802.16j Multihop Relay Network

IEEE 802.16j is an amendment to the IEEE 802.16 broadband wireless access standard to enable the operation of multihop relay stations (RSs). It aims to enhance the coverage, per user throughput of IEEE 802.16e. Comparing with a base station (BS), RS does not need a wireline backhaul and has much lower hardware complexity. Moreover, using RSs can significantly reduce the deployment cost of the system. Unfortunately, there are some tradeoffs in the case of multi-hop RSs. Subscriber stations (SSs), located in a long distance, are suffered from the bottleneck of multi-hop, throughput degradation, and increasing of end-to-end delay. This paper proposes a network coding-based relay scheme for multi-hop relay networks, called NC-BR. It allows RSs to combine two wireless backhaul transmissions into one using the network coding technique. This paper also proposes an improved OFDMA frame structure design for the multi-hop relay network. This technique provides higher utilization for the relay zone by reorganizing the RSs transmission sequence. The analysis and simulation results confirm that the proposed scheme can enhance the throughput gain up to 140% and reduce the end-to-end delay by up to 83%. The simulation results also show that the proposed scheme can reduce the jitter by up to 58%

Active Learning of Nondeterministic Finite State Machines

We consider the problem of learning nondeterministic finite state machines (NFSMs) from systems where their internal structures are implicit and nondeterministic. Recently, an algorithm for inferring observable NFSMs (ONFSMs), which are the potentially learnable subclass of NFSMs, has been proposed based on the hypothesis that the complete testing assumption is satisfied. According to this assumption, with an input sequence (query), the complete set of all possible output sequences is given by the so-called Teacher, so the number of times for asking the same query is not taken into account in the algorithm. In this paper, we propose LNM*, a refined ONFSM learning algorithm that considers the amount for repeating the same query as one parameter. Unlike the previous work, our approach does not require all possible output sequences in one answer. Instead, it tries to observe the possible output sequences by asking the same query many times to the Teacher. We have proved that LNM* can infer the corresponding ONFSMs of the unknown systems when the number of tries for the same query is adequate to guarantee the complete testing assumption. Moreover, the proof shows that our algorithm will eventually terminate no matter whether the assumption is fulfilled or not. We also present the theoretical time complexity analysis of LNM*. In addition, experimental results demonstrate the practical efficiency of our approach