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IEEE 802.15.3 고속 무선 PAN(Personal Area Network)에서 링크상태에 따른 동적 채널할당
곽동원,이승형 한국통신학회 2004 韓國通信學會論文誌 Vol.29 No.7A
무선통신에서의 전송 매체인 air interface는 주위의 여러 환경적인 요인에 의해서 다양한 에러가 존재할 수 있다. 이러한 조건에서는 채널에 대한 신뢰도가 유선일 때보다 크게 떨어지며 더욱이 ad hoc 환경인 IEEE 802.15.3 High-rate WPAN에서는 이러한 에러에 대한 의존도가 더욱 클 수 있다. 이미 WLAN에서 이와 관련된 연구가 있었으며 그 중 하나가 각 무선 노드들의 큐 상태에 따라서 큐의 크기가 크다면 채널 상태가 나쁘다고 판단하고 그 무선 노드에게 할당할 리소스를 줄이는 방법이나. 이는 중앙의 controller가 항상 각 노드들을 모니터링하고 있어야 하는 단점이 있다. 그래서 이러한 단점을 보완하고자 본 논문에서는 무선 이동노드의 위치에 의해 달라지는 링크의 에러 상태에 따라 controller가 노드들에게 할당하는 채널 시간의 크기를 동적으로 변화시켜서 piconet 전체의 throughput을 향상시킬 수 있는 MAC을 제안한다. Various types of error are caused due to many factors of various environment in air interface channel of wireless communications. In this case, the reliability of the channel is much lower than that of wired case. IEEE 802.15.3 high-rate WPAN, which operates in an ad hoc networking environment, is more susceptible to such errors. The problem has been investigated for wireless LANs, for example, as follows. If the queue size of a certain node is longer than that of other nodes, the node estimates that its channel state is bad and the resource of the node is decreased. However this method has a disadvantage that a central controller must always monitor the status. To avoid this disadvantage, in this paper, a new MAC protocol that the throughput of overall piconet is increased by LDS (Link-status Dependent Scheduling) is proposed.
곽동원,이혜미,김동욱 대한평형의학회 2020 Research in Vestibular Science Vol.19 No.3
Objectives: Benign paroxysmal positional vertigo (BPPV), a common cause of vertigo in the elderly, shares common pathogenic mechanisms with osteoporosis. We investigated the efficacy and safety of intravenous zoledronic acid in elderly patients with BPPV and osteoporosis. Methods: We performed a 3-year observational study with elderly patients who were diagnosed with BPPV and osteoporosis. The recurrence of BPPV and changes in bone mineral densitometry (BMD) scores were evaluated one year after the administration of intravenous zoledronic acid. Results: We enrolled 101 elderly patients with BPPV and 54 of them (53.5%) met the diagnostic criteria for osteoporosis. Intravenous zoledronic acid was administered in 51 patients. The recurrence of BPPV was observed in only two of 49 patients (4.1%) at 1 year’s follow-up. The mean lowest T-score of BMD improved from –3.23±0.51 to –3.05±0.58 (p=0.001). Conclusions: Our study showed that the treatment of osteoporosis can be considered to prevent the recurrence of BPPV in the elderly. Further placebo-controlled studies are needed to estimate accurately the efficacy of zoledronic acid in the prevention of recurrence of BPPV in the elderly.
곽동원 한국국가안보국민안전학회 2017 한국국가안보·국민안전학회지 Vol.4 No.-
본 연구는 제주자치경찰제도 도입 및 시행에 관하여 제주자치도민들이 인지하고 있는 시행효과, 관여도, 지지도 및 조직지속성 간에 어떠한 관계가 있는지를 규명하는데 그 목적 을 두고 있다. 연구 대상자는 2016년 거주지가 제주특별자치도로 등록된 주민 650명을 대상으로 선정 하여 편의표본추출법(convenience sampling)을 이용하여 표본을 추출하였으며, 설문지 작성 은 자기평가 기입법을 활용하였다. 회수된 650부 설문지 중 불성실 응답에 대한 150부를 제외한 총 500부의 자료를 본 연구의 데이터로 사용하였다. 구체적인 분석 방법으로는 연 구 대상자의 사회 인구학적 특성을 분석하기 위하여 빈도 분석(Frequency Analysis) 및 기술 분석(Descriptive Analysis)을 실시하였으며, 측정도구의 타당도를 검증하기 위하여 탐색적 요인분석(EFA: Exploratory Factor Analysis)을 실시하였다. 또한 신뢰도 검증을 위해 Cronbach’s Alpah 계수를 산출하였다. 그리고 변수들 간의 관계 유의성을 살펴보기 위하여 상관관계 분석(Pearson’s Correlation Analysis)을 실시하였으며, 사회인구학적 특성에 따른 연구변인 간의 차이를 검증하기 위하여 독립 t-test, One-way ANOVA, Scheffe 사후검정을 실시하였다. 구조 모형을 통한 가설 검증을 실시하였다. 제주자치경찰제도의 시행효과, 관 여도, 지지도, 조직지속성 간의 구조분석을 통한 모형의 적합도는 적합도 지수(CFI, TLI, RMSEA, X2 , df, p, CFI, TLI, RMSEA)에 의해 판정하였다. 이러한 연구의 결과는 지방자치경찰제도의 운영의 발전에 기여하여 활성화를 도모하고 점진적으로 확대를 할 수 있도록 하기 위한 자료로서 가치가 높을 것으로 사료된다. The purpose of this study is to establish what relationship is between trial effect, involvement, approval rating, and organization durability that the inhabitants of Jeju Special Self-Governing Province recognize of introduction and enforcement of Jeju autonomous police system. Objects of the study were 650 residents whose registered residence is Jeju Special Self-Governing Province in 2016, so samples were extracted by using convenience sampling, and drawing up a questionnaire was used by selfadministration. Total 500 questionnaires except for 150 questionnaires with faithless answers of 650 collected questionnaires were used as data of the study. After data whose survey is completed was encoded for each purpose and then was input, two programs such as SPSS(Statistical Package for the Social Science) 18.0 for Windows and AMOS 18.0 were used. As detailed analytical method, Frequency Analysis and Descriptive Analysis were conducted to analyze the sociodemographic features of the study objects, and EFA(Exploratory Factor Analysis) was conducted to verify validity of measuring instrument. In addition, Cronbach’s Alpah coefficient was calculated to verify the reliability. And Pearson’s Correlation Analysis was conducted to examine relation significance between variables, and independent t-test, One-way ANOVA, and Scheffe post test were conducted to verify a difference between study variables according to the sociodemographic features. Hypothesis testing was conducted through structural model. Goodness of Fit of the model through structural analysis between trial effect, involvement, approval rating, and organization durability of Jeju autonomous police system was judged by goodness of fit index(CFI, TLI, RMSEA, X2, df, p, CFI, TLI, RMSEA), and the following results were gained through these analysis and verification. A result of this study will be valuable as a material that promotes and expands invigoration by contributing to development of operation of local municipal police system.