Performance improvement in mobile ad-hoc networks.

The objective of this research is to enhance the network performance under realistic mobile ad-hoc networks environments without modification of the standard. Overview of this research is summarized as follows: First, a packet-fragmentation technique to improve network throughput under the worst channel conditions is proposed. While the conventional packet-fragmentation technique research focuses only on random-bit errors, the proposed technique employs both random bit errors and hidden-node collisions. The analytical models based on Markov-chain model shows that the optimal fragmentation technique can effectively reduce the number of retransmissions caused by both collisions from hidden nodes and corrupted packets by random bit errors, and eventually improving throughput in noisy VANETs channels. As a second contribution, a dynamic service-channel allocation (DSCA) scheme is proposed to maximize the network throughput by dynamically assigning different service channels to the users. The theoretical analysis in this thesis will consider wireless access in the vehicular environment (WAVE) protocol, which is the main characteristic of the vehicular ad-hoc networks standard (the IEEE 802.11p). To summarize, the main contribution of this research is that two schemes will improve the network throughput significantly without modification of the standard. Therefore, there is no implementation issue to deploy the proposed schemes in real devices.PhDCommittee Chair: Copeland, John; Committee Co-Chair: Chang, Yusun; Committee Member: Ammar, Mostafa; Committee Member: Beyah, Raheem; Committee Member: Owen, Henry; Committee Member: Taylor, Davi

Implementation Of Automated Systems For Target Cost Management And Assessing Performance: A Case Study In A Global Automobile Component Company

We examine the implementation of automated systems for target cost management and assessing firm performance in global automobile component company. After financial crisis, companies need to make strategic decisions as fast as possible. However, global companies are difficult to make fast decisions because of taking time for sorting the internal data through oversea companies. Also there are difficult to build systems of cost management and assessment of performance achievement. In this study, as we explain elaborately about the automatic process of cost management and assessment of performance achievement systems in global automobile component companies, we provide practical implications of this benchmark case for other companies’ automated target cost management systems and assessing performance system’s innovations

Schwannomatosis of the tibial nerve

Schwannoma is the most common type of benign tumor arising from the sheaths of the peripheral nerves. It occurs as a solitary tumor in most cases, but when it appears in multiple forms, it is necessary to differentiate it from plexiform schwannoma, schwannomatosis, neurofibroma and malignant peripheral nerve tumors. The authors experienced schwannomatosis in the tibial nerve without the features of neurofibromatosis type 2, so here we present a case report and literature review

Is Foreign Direct Investment Effective From The Perspective Of Tax Avoidance? An Analysis Of Tax Avoidance Through The International Transfer Pricing Behaviors Of Korean Corporations

This study examines whether multinational companies carry out tax avoidance through subsidiaries. An empirical analysis was conducted of 4,585 Korean firms from 2001 to 2010 by company and year. The results are as follows. First, MNCs that have become more internationally diversified through the establishment of overseas subsidiaries generally show a higher tendency to avoid tax. Thus, the analysis results show a positive correlation between globally diversified MNCs and corporate tax avoidance. This correlation is established due to the firms' active use of tax strategies (investment tax credits, tax cuts) applicable to the various countries in which they have expanded their businesses. Second, the analysis results showed that these firms actively avoided tax with overseas transfer pricing behaviors when compared to companies without overseas subsidiaries. Thus, the adjustment of sales prices and purchase value through actual transactions increased the propensity of the parent company to avoid tax.

Construction and nonnegativity of sign idempotent sign pattern matrices

AbstractIn this paper, we modify Eschenbach’s algorithm for constructing sign idempotent sign pattern matrices so that it correctly constructs all of them. We find distinct classes of sign idempotent sign pattern matrices that are signature similar to an entrywise nonnegative sign pattern matrix. Additionally, if for a sign idempotent sign pattern matrix A there exists a signature matrix S such that SAS is nonnegative, we prove such S is unique up to multiplication by -1 if the signed digraph D(A) is not disconnected

The Relationship Between Chaebol And Firm Value Using Bayesian Network

The purpose of this study is to analyze the effects of being a chaebol company, the biggest company characteristic variable, on firm value. It tries to overcome the limitation of multiple regression analysis mostly used in preceding research. That is, as multiple regression analysis assumes uniform linearity between dependent and independent variables, it could not reflect the diverse types of the real world. Thus, based on being a chaebol company and financial information, company characteristic variables influencing firm value, this study derives causal relationships existing between them. The results could help managers and various accounting information users in their decision-making by providing them with information of what company characteristics would directly or indirectly influence firm value. To this end, this study utilizes Bayesian Network and attempts Markov Blanket. In the end, all the analysis methods used in this study not only provides significant results, but also raises its practical value by offering information of diverse situations that could occur in the real world