• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.78-89
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• 2006

In development of network-enabled consumer electronics, much of the time and effort is spent analyzing and solving network performance problems. In this paper, we define an instance of such problems discovered while developing a commercial home network gateway. We then analyze its cause and propose a solution mechanism. Our home network gateway uses art asymmetric link (ADSL) and suffers from an undesirable phenomenon where downlink traffic interferes with upload speed. We call this phenomenon the network performance interference problem. While this problem can easily be confused with receive livelock caused by packet contention at the input queue, we and that this is not the case. By performing extensive experiments and analysis, we reveal that our problem is caused by packet contention at the output queue and certain intrinsic characteristics of TCP. We devise an ACK-separation queuing mechanism for this problem and implement it in the home network gateway Our experiments show that it effectively solves the problem.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1412-1422
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• 2010

A bistatic radar using the pulse chasing can detect a target to track successive transmitted pulses using a receive beam for effectively scanning the cosite search area. When tracking a transmitted pulse with the receive beam, some beam pointing errors within pulse-to-pulse can cause the timing error in received pulse and the variation of the signal strength. In this paper, we have proposed that some errors due to the receive beam pointing error could limit the MTI filter's performance and derived that the relationship between the MTI performance and the geometric factors which are the inherent properties in bistatic configuration. Through the simulation, we have considered the limitations of the improvement performance restricted by the receiving beam pointing error and confirmed the contribution to the performance improvement in maintaining the receiving beam pointing error of under 0.5 degrees.

• Journal of Korean Academy of Nursing
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• v.26 no.3
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• pp.697-708
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• 1996

Most efforts to improve tuberculosis treatment adherence target the patient and his or her behavior. This study examined the effects of behavioral modification training for these patients. Based on Bandura's behavioral principles of modeling, intervention strategies using a video program were devised to elicit specific patient target behaviors considered to improve patients' adherence to tuberculosis treatment regimens. A random assignment, two-group(experimental group and control group) research design including 81 subjects was used. The main outcomes measured were pill taking measured with the Medication Event Monitoring System(MEMS) Medication Cap, patients' self-efficacy, and their knowledge of tuberculosis. The findings are as follows : 1) There was a significant difference between the experimental group and the control group in patients' feelings of self-efficacy. That is, the patients who received the behavior modification program showed greater feeling of self-efficacy to initiate and change their behavior for the tuberculosis treatment regimen than the patients who did not receive the program(t=3.51, p=0.01). 2) There was a significant difference between the experimental group and the control group in patients' knowledge of tuberculosis. That is, the patients who received the behavior modification program showed higher level of knowledge of tuberculosis than the patients who did not receive the program(t=2.15, p=0.03) 3) There was a significant difference between the experimental group and the control group in patients' adherence to tuberculosis treatment regimens. That is, the patients who received the behavior modification program showed greater adherence to the treatment regimens than the patients who did not receive the program(t=5.11, p=0.00). The study findings provided useful insights into nursing practice, particularly in planning intervention strategies aimed at enhancing patients' adherence in tuberculosis that may also be relevant to other chronic diseases with patient adherence problems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8B
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• pp.1348-1356
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• 2000

In this paper, we proposed a trellis coded Multi-Carrier CDMA 16 QAM system with multiple transmit/receive antenna diversity technique, which is simple and suitable for indoor wireless communications. The proposed multiple transmit/receive antenna diversity technique is that the transmitter sends a trellis coded Multi-Carrier CDMA 16 QAM signal from multiple transmitting antennas with intentional time delays, which makes a receiver possible to distinguish and combine the signals from different antennas. In wireless indoor communication system, if we allow the increase of the complexity of the system, it is also possible to achieve additional diversity gain in the performance with the combination of the proposed technique and the conventional receiving antenna diversity. Furthermore, we have found that the proposed trellis coded Multi-Carrier CDMA 16 QAM system, which employs multiple transmit/receive antenna, is less sensitive to the multiple user interference and fading than conventional receiving antenna diversity systems.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.85-94
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• 2013

This paper presents a novel mobile measurement system with multi antennas which enable mobile measurement as well as fixed measurement with telescope mast. Proposed system installed 4 omni directional antennas for the space diversity process and one directional log periodic antenna for the simultaneous conventional fixed measurement. Whole antenna systems are connected to the custom DTV channel analyzers with Ethernet networks respectively and processed by the main controller to calculate real time average receive levels. To prove the performance of proposed system, the typical receive models are categorized as 3 area types - open area, building area and house area, and then intensive field tests were performed through mobile and fixed measurement phases. With these measurement data, the relationships between mobile and fixed measurement are analyzed, and the concept of compensation factor is proposed to assume the average receive level of signal. The field test is fulfilled as a co-work with public broadcasters and the proposed system is applied to the intensive coverage measurement projects for metropolitan areas by the korean government agencies.

• Convergence Security Journal
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• v.12 no.3
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• pp.107-113
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• 2012

Due to the development of communications technology, it is now possible to be offered online from remote places. This kind of communications technology can be applied to the medical field. The medical treatment appointments in hospitals can be its typical example. But still, in most of hospitals, patient or guardian have to physically visit or call to the hospital to set up an appointment for the medical treatment. In addition, they have to wait in line in order to pay after receiving the medical treatment. The patient or guardian, after paying, receive a paper prescription and they go to a nearby pharmacy to take the medicines. They must wait in line again there in order to receive the medicine from the pharmacy. In this paper, we would like to suggest a smart medical treatment system in order to solve the problems discussed above. With this proposed system, the user will be able to make an appointment, make payments and receive medication quickly and easily without spending extra time. Also, there will be no need for paper prescriptions with this system. We discuss about the security of medical information for this proposed smart medical treatment system proposed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.12
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• pp.1380-1387
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• 2012

The transmit/receive(T/R) module is a key component in the active phased array system. The brick-type T/R module has been widely used and the miniaturization has been an important factor to get the flexibility of the system configuration. For the miniaturization, multi-function chips(MFC) having a common leg configuration are suitable to reduce the number of required MMICs and a high isolation between transmit and receive paths is necessary for the high gain T/R modules. In this work, we propose a bias timing scheme for the compact T/R module and show the optimum timing based on measurements, in order to improve the feed-back path loop problem and the consequent isolation problem of the common leg configuration. We have implemented high power(7 W/channel) and high T/R gain(35 dB transmit and 30 dB receive gains) within the half size($140{\times}80{\times}16mm^3$) of the conventional T/R modules.

• Journal of Family Resource Management and Policy Review
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• v.15 no.4
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• pp.107-127
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• 2011

The purpose of this study is to examine demographic characteristics, psychological characteristics and patterns of supportive relationships with their children that affect the successful lives of the elderly. A survey was conducted of 410 people aged between 65 and 85, and 405 samples were used for the analysis. First, the supportive relation between the elderly and their children was categorized into four groups depending on the total amount and direction of support. The four groups consisted of the elderly who exchanged little or no support, those who only received support from their children, those who only gave support, and those who both gave and received support. Second, the more the elderly exchanged support and gave emotional support to their children, the better the chance that the elderly would lead a successful life in later years. Third, subjective health conditions most significantly affected the successful lives of the elderly who exchanged little or no support. The level of education was most significant for the elderly who only received support. The level of housing satisfaction mostly affected the elderly who only gave support. Mutual support primarily affected the elderly who both gave and received. Thus, we should provide health programs for the elderly who exchange little or no support to encourage a healthier lifestyle. In addition, opportunities for continuing education should be provided for the elderly who only receive support to make up any deficiency in education. Because spouses are mostly affected for those elderly who exchange little or no support and the elderly who only receive support, we should provide educational programs about how to be better lifetime companions to each other and also provide medical and in-home care for the remaining spouse even after the other partner is gone. Because housing satisfaction greatly affects the elderly who only give support, improvements in the residential environment are essential. Since the level of mutual support is crucial to the elderly who both give and receive support, programs on the development of human resources are needed for the elderly to interact dynamically and intimately with their children.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.289-294
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• 2014

In this paper, we investigate the user scheduling, transmit beamforming, and receive beamforming of uplink space division multiple access (SDMA) systems where multiple users are allowed to transmit their signal to a base station (BS) using the same frequency band simultaneously. The BS performs a receive beamforming using the predetermined pseudo-random pattern and select users with a specific criterion. Especially, in this paper, we propose the threshold-based transmit power control, in which a user decrease its transmit power according if its generating interference to other users's signal is larger than a predetermined threshold. Assuming that the TDD system is used, the channel state information (CSI) can be obtained at each user from pilot signals from the BS. Simulation results show that the proposed technique significantly outperforms the existing user scheduling algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2121-2126
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• 2007

In this paper, the performance improvement of ultra-wideband(UWB) communications system to achieve high-data-rate using spatial diversity provided by multiple receive antennas is investigated. We derive the expression for the received SINR after spatially combining through multiple receive antennas and evaluate the bit error rate(BER) performance by numerical simulation. We also compare the performance results in the case of 2PPM systems with the theoretical performance results in the case of 2PAM THMA UWB systems. The impacts of spatial diversity on the performance of 2PPM and 2PAM THMA UWB systems are analyzed. It is shown that the BER performance is improved as the number of receive antennas increases. Also, it is observed that in the presence of multiple user interference signals, the performance of 2PAM THMA UWB systems is considerably superior to that of 2PPM THMA UWB systems.