• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.5
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• pp.107-116
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• 2011

In this paper, a traffic adaptive sleep based medium access control (TAS-MAC) protocol for wireless sensor networks (WSNs) is proposed. The protocol aims for WSNs which consist of clustered sensor nodes and is based on TDMA-like schema. It is a typical schedule based mechanism which is adopted in previous protocols such as LEACH and Bit-Map Assisted MAC. The proposed MAC, however, considers unexpected long silent period in which sensor nodes have no data input and events do not happen in monitoring environment. With the simple traffic measurement, the TAS-MAC eliminates scheduling phases consuming energy in previous centralized approaches. A frame structure of the protocol includes three periods, investigation (I), transmission (T), and sleep-period (S). Through the I-period, TAS-MAC aggregates current traffic information from each end node and dynamically decide the length of sleep period to avoid energy waste in long silent period. In spite of the energy efficiency of this approach, the delay of data might increase. Thus, we propose an advanced version of TAS-MAC as well, each node in cluster sends one or more data packets to cluster head during the T-period of a frame. Through simulation, the performance in terms of energy consumption and transmission delay is evaluated. By comparing to BMA-MAC, the results indicate the proposed protocol is more energy efficient with tolerable expense in latency, especially in variable traffic situation.

• Journal of KIISE:Information Networking
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• v.33 no.5
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• pp.355-368
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• 2006

This paper introduces a new split-TCP approach for improving TCP performance over IEEE 802.11-based wireless LANs. TCP over wireless LANs differently from wired networks is not aggressive, which is a fundamental reason for poor performance. Therefore, we propose TAS (TCP-Aware Sub-layer) to migigate this problem. Our scheme extends the split-connection approach that divides a connection into two different connections at a split point such as an access point (AP). Using TAS, a wireless node emulates TCP ACK packets using MAC ACK frames, instead of receiving real TCP ACK packets. We compared TAS with both normal TCP and I-TCP (Indirect TCP) by NS2 simulation. Results show that TAS achieves higher throughput, more fair resource allocation and, in power-saving mode, shorter delays.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.15 no.1
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• pp.29-46
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• 2011

Objectives: The purpose of our study is to develop and verify questionnaire using temperament and character inventory (TCI) in the future by contemplating the comparative study on TCI and psychological testing Questionnaires. Methods: We investigate the research searched by keyword: 'TCI' and 'Questionnaire' through internet search engines, Pub Med, Science Direct and Springer Link. Results: The comparative study of TCI and psychological testing Questionnaires(SPAQ, BDI, TAS-20, MAC, DSQ) which have the purpose of diagnosing personal disorder is helpful for the verification of the level of adequacy of the concerned psychological testing Questionnaire and contributes to the understanding of psychobiological characteristics of each of personal disorders. The comparative study of TCI and psychological testing Questionnaires(MMPI, NEO, CPI) which have the purpose of comprehending general personality is helpful for the verification of the level of adequacy of the concerned psychological testing Questionnaire and contributes to the understanding of meaning of questionnaire-scales. The comparative study of TCI and constitution-psychological testing Questionnaire(QSCC II) is helpful for the verification of the level of adequacy and the understanding of the concerned constitution-psychological testing Questionnaire and contributes to the understanding of psychobiological characteristics of each of constitutions. Conclusions: TCI is a useful tool to understand the psychological testing Questionnaire more deeply and verify the level of the adequacy, and from now on for the development and verification of Oriental medicinal-psychological testing Questionnaire, the study comparing it with TCI should be actively used.