• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.1
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• pp.7-21
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• 2017

Multiple antenna techniques employed in fourth generation mobile communication systems are affected on their performance mostly by transmission environments and antenna configurations. The performance of the indoor LTE(Long-term Evolution) MIMO(multiple input multiple output) has been rigorously evaluated with considering various diversity transmission schemes and propagation conditions in the paper. Specifically, MAC TP(medium access control throughput) and LTE system parameters related to the MIMO technique are analyzed for several indoor propagation conditions. The performance comparison between multiple antenna diversity mode and single antenna mode has been derived as well. The results performed in the paper give the guideline on antenna configurations of polarization diversity in LTE 2×2 MIMO for various indoor channel environments, and possibly are exploited by network operators and antenna manufacturers.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.1
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• pp.186-191
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• 2009

In the study on the waveform analysis of radial artery pulse diagnosis, we need to establish fundaments of contemporary pulse diagnosis research. As we will to do experimental research on the difference of pulse waveform on the radial artery with applied variations of pressure(5 stage-pressure) and measuring position(CHON, KWAN, CHEOG). First of all, in this research, we did the experiment of the study on the waveform analysis of radial artery(left KWAN) pulse dignosis by using 3 dimension pulse meter and analyzer (3D MAC). As a result. we extracted the seven measurement fluents : energy(E), size of cycle(h1), size of reflection cycle(h2), time of reflection cycle(t2), time of contraction (t4), width of cycle(w), area of waveform(A) by the statistically reasonable differences. We expect that the seven measurement fluents contribute to divide the situation through the results of waveform analysis of radial artery.

• Korean Journal of Adult Nursing
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• v.20 no.3
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• pp.395-405
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• 2008

Purpose: The purpose of this study was to develop a Web-based flash content for fighting spirit promotion and to test its effect on cancer patients' fighting spirit. Methods: The 15-minute long Web-based flash content was developed using the following 5 process: analysis, planning, development, program operation and evaluation stages and utilized the multiple edition and revision processes from December 2005 to August 2006. The evaluation was done by one group pretest-posttest design. Study subjects were 17 cancer patients undergoing chemotherapy. The group were received a 2-week intervention, a day weekly, and measured the variables at baseline, 4 weeks later. The study was performed from August 2006 to February 2007 at a cancer center in Korea. Fighting spirit was measured by Mini-MAC(Mental Adjustment to Cancer). Data was analysed by descriptive statistics and paired t-test using SAS 9.13 program. Results: On the Web-based flash content, there are 4 menu bars that consisted of cancer diagnosis, symptom management, stress management, and cancer survivorship. The study group revealed significantly more fighting spirit than pre-test(t=-3.04, p=.008). Conclusion: This Web-based flash content can be utilized in psychosocial interventions for promoting fighting spirit in patients with cancer.

• Asian Oncology Nursing
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• v.9 no.2
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• pp.136-144
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• 2009

Purpose: This study was to compare the differences in self-care behaviors between the group with fighting spirit and the group with helplessness. Methods: This study utilized a cross-sectional descriptive design. A total of 97 ambulatory cancer patients completed the Mental Adjustment to Cancer (MAC) scale by Watson et al. (1988) and Self Care Behaviors Scale by Oh et al. (1997). The data was analysed using frequency, percentage, t-test, ANOVA, Pearson's correlation and stepwise multiple regression. Results: Fighting spirit group were found to conduct self-care behaviors more compared to the helplessness group (t=3.346, p<.0001). The score of the self-care behaviors in fighting spirit group was 4.42 out of a total score of 7 and that of helplessness group was 3.85. There was a significant difference (p<.0001) in self-care behaviors according to the level of faith and performance status. Fighting spirit ($R^2$=0.120, p<.0001), performance status ($R^2$=0.078, p=.001) were predictive of self-care behaviors. Conclusion: Cancer patients' mental adjustment is correlated with the degree of self-care behaviors. Having fighting spirit is one of the most adaptive techniques that cancer patients could use in adjustment to the life with cancer.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.213-220
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• 2008

This paper analyzes a broadcasting technique for wireless multi-hop sensor networks that uses a form of cooperative diversity called opportunistic large arrays (OLAs). We propose a method for autonomous scheduling of the nodes, which limits the nodes that relay and saves as much as 32% of the transmit energy compared to other broadcast approaches, without requiring global positioning system (GPS), individual node addressing, or inter-node interaction. This energy-saving is a result of cross-layer interaction, in the sense that the medium access control (MAC) and routing functions are partially executed in the physical (PHY) layer. Our proposed method is called OLA with a transmission threshold (OLA-T), where a node compares its received power to a threshold to decide if it should forward. We also investigate OLA with variable threshold (OLA-VT), which optimizes the thresholds as a function of level. OLA-T and OLA-VT are compared with OLA broadcasting without a transmission threshold, each in their minimum energy configuration, using an analytical method under the orthogonal and continuum assumptions. The trade-off between the number of OLA levels (or hops) required to achieve successful network broadcast and transmission energy saved is investigated. The results based on the analytical assumptions are confirmed with Monte Carlo simulations.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.283-288
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• 2019

LPWA (Low Power Wide Area) networks have been considered as one of the technologies which can be implemented in IoT (Internet of Things) applications by providing less power and longer communication range compared with existing wireless technologies. In this paper, we investigate LoRa which is one of representative technologies for LPWA networks. First, we present general properties and several technologies of LPWA networks. Then, the technical specification, properties, and pros/cons of LoRa are studied. Finally, we discuss analysis of LoRa's performance and its ehancement technologies by focusing on physical layer and MAC (Medium Access Control) layer.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.6
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• pp.1849-1876
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• 2022

Wireless Sensor Network (WSN) is considered as an integral part of the Internet of Things (IoT) for collecting real-time data from the site having many applications in industry 4.0 and smart cities. The task of nodes is to sense the environment and send the relevant information over the internet. Though this task seems very straightforward but it is vulnerable to certain issues like energy consumption, delay, throughput, etc. To efficiently address these issues, this work develops a cross-layer model for the optimization between MAC and the Network layer of the OSI model for WSN. A high value of duty cycle for nodes is selected to control the delay and further enhances data transmission reliability. A node measurement prediction system based on the Kalman filter has been introduced, which uses the constraint based on covariance value to decide the scheduling scheme of the nodes. The concept of duty cycle for node scheduling is employed with a greedy data forwarding scheme. The proposed Duty Cycle-based Greedy Routing (DCGR) scheme aims to minimize the hop count, thereby mitigating the energy consumption rate. The proposed algorithm is tested using a real-world wastewater treatment dataset. The proposed method marks an 87.5% increase in the energy efficiency and reduction in the network latency by 61% when validated with other similar pre-existing schemes.

• Korean Journal of Clinical Pharmacy
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• v.22 no.2
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• pp.123-130
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• 2012

거대세포바이러스(Cytomegalovirus; CMV) 감염은 동종조혈모세포이식 환자의 주요 사망원인 중 하나이다. 용량감소전처치(Reduced-intensity conditioning; RIC)를 이용한 조혈모세포이식은 골수억제전처치(Myeloablative conditioning; MAC)에 비해 골수억제 및 면역억제가 적으므로 CMV 감염 발생율을 감소시킬 것이라 예상되었으나 예방적 면역억제요법, T세포 제거 약제의 사용 등으로 서로 상이한 결과가 보고되고 있다. 2007년 1월부터 2009년 12월까지 총 141명의 환자(MAC 113명, RIC 28명)가 동종조혈모세포이식을 받았으며, CMV 감염은 MAC 62.8%, RIC 57.1% (p = 0.310), CMV 질환은 각각 12.4%, 14.3% (p = 0.785)에서 발생하였다. CMV 감염/질환 발생빈도와 CMV 항원 혈증검사 지속기간, 초기/최고치, 생존율은 두 군간 유의한 차이가 없었다. CMV 감염 위험인자에 대한 다변량분석 결과, 환자가 고령일수록(HR 1.024, 95% CI 1.002-1.045; p = 0.031) 또는 grade 2 이상의 급성 이식편대숙주병이 발생한 경우에(HR 1.849, 95% CI 1.031-3.315; p=0.039) CMV 감염 발생 위험율이 유의하게 높았다. 결론적으로, 전처치요법 강도에 따른 CMV 감염의 발생빈도와 발현양상의 차이는 없었으나, 고령이거나 grade 2 이상의 급성 이식편대숙주병이 발생한 환자의 경우 CMV 감염 발생과 유의한 연관성을 보였다. 이상과 같은 결과에 비춰 봐서 CMV 질환이 대부분 이식 100일 이후에 발생한 점을 고려할 때, 이식 후 CMV 감염 발생 시 ganciclovir 선제요법과 함께 이들 환자들에게 지속적인 모니터링을 실시하는 것이 필요할 것으로 사료된다.

• Korean Association of Arts Management
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• no.59
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• pp.73-99
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• 2021

Free admission policies have been gradually extended for the public to use cultural facilities free of charge, which lowered the barriers to use those facilities and has a great effect on increasing visitor demands. However, the annual number of visitors which is open to the public isn't quite accurate and varies from institution to institution, which means just a head count. Especially people counter overestimates the number of visitors because it counts visitors in duplicate. Therefore, the purpose of this study is to prepare effective way of grasping the number of visitors using cultural infrastructure. First, comparable number of visitors should be measured by defining the notion of visitor clearly, which has been measured vaguely. Secondly, the problem of duplicate count, which is considered the most problematic, should be solved. Thirdly, the various analysis of visitor behavior should be conducted to provide a high-quality service. To work out the problems above, new measurement will be presented here. This study suggests a state-of-the-art wireless signal-based measurement that could eliminate the duplicate data by collecting MAC address -smart device's distinct signal value. And it also could analyze diverse visitor behaviors by understanding a flow of visitor traffic, duration of stay and revisitation. I would like to examine the possibility and effectiveness of this new measurement by testing it.

• Electronics and Telecommunications Trends
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• v.29 no.4
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• pp.110-122
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• 2014

무선환경은 가짜 클론 디바이스가 진짜인 것처럼 위장한 해킹공격에 매우 취약한 것으로 잘 알려져 있다. 그것은 단말기와 기지국(AP: Access Point)이 위변조가 쉬운 디바이스 식별자(예로 MAC(Medium Access Control) 주소, SSID, BSSID(Basic Service Set Identification) 등)를 이용하여 상호 인증하기 때문이다. 무선핑거프린팅(Wireless Fingerprinting)은 통신과정에서 발생되는 무선신호 특성으로부터 디바이스를 고유하게 식별하는 핑거프린트를 추출하여 송신 디바이스가 가짜 클론 디바이스인지 아닌지 여부를 식별하는 기술이다. 본 기술은 무선물리계층 보안을 위한 인증 및 키 생성, 무선 침입탐지, 공격자의 위치/방향/거리 추적, 무선 포랜식 및 보안관제의 성능을 결정하는 핵심기술로 활용되고 있다. 향후 등장이 예상되는 M2M 무선랜, 무선인지네트워크, 무선센서, 무선차량통신, IoT 무선통신환경에서도 본 기술의 중요성은 더욱 증가하리라 본다. 본고에서는 무선 디바이스의 핑거프린팅 개념을 이해하고, 기술 분류에 따른 세부기법 연구 및 보안응용 동향을 분석함으로써 본 기술의 발전방향을 조망해보고자 한다.