• 전기전자학회논문지
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• 제16권2호
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• pp.81-85
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• 2012

본 논문에서는 macro-cell 위에 동일한 주파수를 쓰는 pico-cell이 overlay 되어 있는 환경에서, 움직이는 사용자에 대한 management 방법이 움직이는 사용자가 지원 받을 수 있는 data rate에 미치는 영향을 분석한다. 이러한 분석을 통해 mobility management 방식에 따른 움직이는 사용자가 지원받을 수 있는 data rate는 사용자와 pico-cell의 상대적 위치에 의존함을 확인하였다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2002년도 춘계학술발표논문집 (하)
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• pp.1393-1396
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• 2002

무선 ATM(Asynchronous Transfer Mode) 망을 기본으로 하여 ATM망에서 사용하는 서비스 종류인 CBR(Constant Bit Rate), rtVBR(Real-Time Variable Bit Rate), nrtVBR(Non-Real-Time Variable Bit Rate), ABR(Available Bit Rate), UBR(Unspecified Bit Rate)에 따른 플로우를 우선 각 서비스 흐름에 따라서 공평하게 패킷 스케줄링 한다. 그리고 각 서비스 종류에 따라 대역이나 지연에 따라 모든 사용자의 다양한 서비스 트래픽에 공평하게 서비스하는 구조를 갖는다. 아울러 무선 통신망 채널에 에러가 발생할 경우를 고려하여 각 서비스 트래픽에 대한 QoS(Quality of Service)를 보장해주는 무선 ATM 통신망에서 동작하는 스케줄링 알고리즘을 제안하여 시뮬레이션과을 통해 기존의 방법과 성능을 비교하여 기존의 유선 통신망 스케줄링 알고리즘과 달리 무선망의 에러에 대한 각 트래픽의 에러에 대한 성능 향상에 대해 알아본다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.165-177
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• 2019

This paper considers corrosion wastage of two ship hull structure members as a part of investigated fuel oil tanks of 25 aging bulk carriers. Taking into account that many factors which influence corrosion wastage of ship hull structures are of uncertain nature, the related corrosion rate ($c_1$) is considered here as a real-valued continuous distribution, assuming that the corrosion wastage starts after 5, 6 or 7 years. In all considered cases, by using available data and applying three basic statistical tests, it is established that between two-parameter continuous distributions, normal, Weibull and logistic distributions are best fitted distributions for the mentioned corrosion rate ($c_1$). Note that the presented statistical, numerical and graphical results concerning two mentioned ship hull structure members allow to compare and discuss the corresponding probabilistic estimates for the corrosion rate ($c_1$).

• 한국통신학회논문지
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• 제22권4호
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• pp.618-636
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• 1997

DQDB(Distributed Queue Dual Bus) protocol, the IEEE 802.6 standard protocol for metropolitan area networks, does not fully take advantage of the capabilities of dual bus architecture. Although fairness in bandwidth distribution among nodes is improved when using so called the bandwidth balancing mechanism, the protocol requires a considerable amount of time to adjust to changes in the network load. Additionally, the bandwidth balancing mechanism leaves a portion of the available bandwidth unused. In a high-speed backbone network, each node may act as a bridge/ router which connects several LANs as well as hosts. However, Because the existence of high speed LANs becomes commonplace, the congestionmay occur on a node because of the limitation on access rate to the backbone network and on available buffer spaces. to release the congestion, it is desirable to install some congestion control algorithm in the node. In this paper, we propose an efficient congestion control mechanism and fair and waster-free MAC protocol for dual bus network. In this protocol, all the buffers in the network can be shared in such a way that the transmission rate of each node can be set proportional to its load. In other words, a heavily loaded node obtains a larger bandwidth to send the sements so tht the congestion can be avoided while the uncongested nodes slow down their transmission rate and store the incoming segments into thier buffers. this implies that the buffers on the network can be shared dynamically. Simulation results show that the proposed probotol significantly reduces the segment queueing delay of a heavily loaded node and segment loss rate when compared with original DQDB. And it enables an attractive high throughput in the backbone network. Because in the proposed protocol, each node does not send a requet by the segment but send a request one time in the meaning of having segments, the frequency of sending requests is very low in the proposed protocol. so the proposed protocol signigificantly reduces the segment queuing dely. and In the proposed protocol, each node uses bandwidth in proportion to its load. so In case of limitation of available buffer spaces, the proposed protocol reduces segment loss rate of a heavily loaded node. Bandwidth balancing DQDB requires the wastage of bandwidth to be fair bandwidth allocation. But the proposed DQDB MAC protocol enables fair bandwidth without wasting bandwidth by using bandwidth one after another among active nodes.

• 인간식물환경학회지
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• 제22권2호
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• pp.219-229
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• 2019

This study was carried out to verify the accuracy of fitness tracking devices in monitoring heart rate and energy consumption and to contribute to the development of a forest exercise program that can recommend the intensity and amount of forest exercises based on personal health-related data and provide monitoring and feedback on forest exercises. Among several commercially available wearable devices, Fitbit was selected for the research, as it provides Open API and data collected by Fitbit can be utilized by third parties to develop programs. Fitbit provides users with various information collected during forest exercises including exercise time and distance, heart rate, energy consumption, as well as the altitude and slope of forests collected by GPS. However, in order to verify the usability of the heart rate and energy consumption data collected by Fitbit in forest, the accuracy of heart rate and energy consumption were verified by comparing the data collected by Fitbit and reference. In this study, 13 middle-aged women were participated, and it was found that the heart rate measured by Fitbit showed a very low error rate and high correlation with that measured by the reference. The energy consumption measured by Fitbit was not significantly different from that measured in the reference, but the error rate was slightly higher. However, there was high correlation between the results measured by Fibit and the reference, therefore, it can be concluded that Fitbit can be utilized in developing actual forest exercise programs.

• 한국토양비료학회지
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• 제19권1호
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• pp.50-55
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• 1986

묘삼생산(苗蔘生産)의 기초자료(基礎資料)를 얻고자 양직묘포(養直苗圃) 32, 반양직묘포(半養直苗圃) 19개포장(個圃場)에서 묘삼수량(苗蔘收量)과 묘포토양(苗圃土壤)의 이(理), 화학성(化學性)을 조사(調査)하고 그들간(間)의 상관관계(相關關係)를 분석(分析)한 결과(結果)는 다음과 같다. 1. 발아율(發芽率)은 양직묘포(養直苗圃) $78.5{\pm}3.0%$, 반양직묘포(半養直苗圃) $77.8{\pm}2.8$였으며 파종입수(播種粒數)에 대(對)한 묘삼총생산본수비율(苗蔘總生産本數比率)(성묘율(成苗率))은 양직묘포(養直苗圃) $62{\pm}13.5%$, 반양직묘포(半養直苗圃) $53{\pm}12.6%$였다. 2. 파종입수(播種粒數)에 대(對)한 사용가능묘삼비율(使用可能苗蔘比率)은 양직(養直) $42{\pm}12.5%$, 반양직(半養直) $26{\pm}12.1%$였으며 사용가능묘삼수(使用可能苗蔘數)는 양직묘포(養直苗圃) $627{\pm}187$본(本)/간(間)(간(間)=$180{\times}90cm$의 면적(面積)), 반양직묘포(半養直苗圃) $368{\pm}182$본(本)/간(間)이었다. 3. 성묘본수(成苗本數)에 대(對)한 불용묘삼수비율(不用苗蔘數比率)은 양직묘포(養直苗圃) 34%, 반양직묘포(半養直苗圃) 51%였다. 4. 지상부생육(地上部生育)과 지하부생육간(地下部生育間)에는 유의상관(有意相關)이 인정(認定)되지 않았다. 5. 양직묘포(養直苗圃)에서 경장(莖長) 및 엽장(葉長)은 조사함량(粗砂含量)과 부(負)의 상관(相關), 극세사함량(極細砂含量)과는 정(正)의 상관(相關)이 각각(各各) 인정(認定)되었다. 6. 사용가능묘삼비율(使用可能苗蔘比率)과 중사(中砂), 세사(細砂) 및 극세사(極細砂)의 총함량(總含量)과 정(正)의 상관(相關), 조사함량(粗砂含量)과는 부(負)의 상관(相關)이 각각(各各) 인정(認定)되었다. 개체근중(個體根重)과 중사(中砂), 세사(細砂) 및 극세사(極細砂)의 함량간(含量間)에 정(正)의 상관(相關)이 인정(認定)되었다. 7. 유기물(有機物), 유효인산(有效燐酸) 및 가리(加里)의 함량(含量)은 양직묘포(養直苗圃)에 비(比)해 반양직묘포(半養直苗圃)에서 많았으나 석회(石灰)의 함량(含量)은 오히려 양직묘포(養直苗圃)에서 많았다. 8. 주당엽면적(株當葉面積)은 유기물함량(有機物含量)과, 경장(莖長)은 석회함량(石灰含量)과 정(正)의 상관(相關)이 각각(各各) 인정(認定)되었고, 지하부생육(地下部生育)과 토양요인간(土壤要因間)에 반양직묘포(半養直苗圃)에서는 개체근중(個體根重)과 유기물(有機物) 및 고토함량간(苦土含量間)에는 각각(各各) 정(正)의 상관(相關)이 인정(認定)되었으나 양직묘포(養直苗圃)에서는 어느 요인(要因)과도 상관(相關)이 인정(認定)되지 않았다.

• 약학회지
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• 제8권1호
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• pp.1-5
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• 1964

Present experiment in vivo shows that some conversions of active groups in chloramphenicol residue of ester, that is hydrolytic cleavage of dichloracetamide and glucuronide formation, seem to take place prior to hydrolysis. This result suggest that the enzymatic hydrolysis rate in vitro, is not available as an index for the evaluation of the chlorampherical ester potency.

• 대한간호
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• 제20권4호통권112호
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• pp.77-85
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• 1981

This study was undertaken in an attempt to identify level of birth and infant death in the KHDI demonstration areas. The objectives of this study are to collect available information on birth and infant death in the KHDI demonstration areas, and estimate

• 한국통신학회논문지
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• 제29권9B호
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• pp.808-817
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• 2004

최근 Low-Rate WPAN 기술에 관한 많은 연구가 진행되고 있다. Low-Rate WPAN 은 사용자가 실질적으로 인식하지 못하는 상황에서도 주변환경에 존재하는 많은 수의 센서를 통해 컴퓨터를 이용한 개선된 서비스제공에 목적을 두고있다. Low-Rate WPAN 환경을 구성하는 센서 디 B} 이스는 빈번한 이동성을 가지게 되고 새로운 경로 탐색을 위한 메카니즘을 필요로 하게 되므로, 본 논문에서는 센서 디바이스의 위치정보를 이용한 Low-Rate WPAN 환경에서의 효율척언 라우팅 메카니즘을 제안한다. 제안한 메카니즘은 기존 방법들에 비해 라우팅 메시지 수를 감소시킬 수 있음을 시뮬레이션을 통해 입증한다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권16호
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• pp.7359-7363
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• 2015

Background: As a result of significant progress made in treatment of many types of cancers during the last few decades, there have been an increased number of patients who do not experience mortality. We refer to these observations as cure or immune and models for survival data which include cure fraction are known as cure rate models or long-term survival models. Materials and Methods: In this study we used the data collected from 438 female patients with breast cancer registered in the Cancer Research Center in Shahid Beheshti University of Medical Sciences, Tehran, Iran. The patients had been diagnosed from 1992 to 2012 and were followed up until October 2014. We had to exclude some because of incomplete information. Phone calls were made to confirm whether the patients were still alive or not. Deaths due to breast cancer were regarded as failure. To identify clinical, pathological, and biological characteristics of patients that might have had an effect on survival of the patients we used a non-mixture cure rate model; in addition, a Weibull distribution was proposed for the survival time. Analyses were performed using STATA version 14. The significance level was set at $P{\leq}0.05$. Results: A total of 75 patients (17.1%) died due to breast cancer during the study, up to the last follow-up. Numbers of metastatic lymph nodes and histologic grade were significant factors. The cure fraction was estimated to be 58%. Conclusions: When a cure fraction is not available, the analysis will be changed to standard approaches of survival analysis; however when the data indicate that the cure fraction is available, we suggest analysis of survival data via cure models.