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불완전매체공유 환경을 위한 CSMA/CA기반 분산방식 매체접근제어기법
이병석,전병욱,최진우,Lee Byoung-Seok,Jeon Byoung-Wook,Choe Jin-Woo 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.5b
We define the incomplete medium sharing system as a multi-channel shared medium communication system where any types of constraints are imposed to the set of channels that may be allocated to any transmitter-receiver node pair. A set of distributed MAC schemes are proposed, all of which are based on the CSMA/CA scheme employed in IEEE 802. 11 WLAN standards. Distributed MAC schemes are proposed in three different forms, which can be differentiated by the number and the location of back-off timers; that is, (1) one timer for all queues destined for different receiver nodes, (2) multiple timers at individual transmission queues, (3) multiple timers for individual channels. Through an extensive set of computer simulations, the performances of the proposed MAC schemes show that the MAC scheme with timers at individual transmission queues outperform the others in terms of throughput and delay for most cases considered. The complexity of the proposed schemes is also compared, and the first scheme obviously turned out to be the simplest, and the complexity of the second and third schemes depends on the number of receiver nodes and the number of channels, respectively. 매체공유기반 통신시스템은 매체접근제어 과정에서 단말기의 채널 점유 제약 조건에 따라 크게 완전매체공유 시스템과 불완전매체 공유 시스템으로 구분할 수 있다. 본 논문에서는 불완전매체공유 시스템의 채널활용효율을 향상시키기 위한 분산식 매체접근제어기법을 제안한다. 제안하는 매체접근제어기법은 IEEE 802.11 무선랜의 CSMA/CA 기법을 확장한 방법으로써 임의 지연 시간을(random backoff time) 채널에 대해 개별적, 집합적, 큐(queue)에 대해 개별적으로 적용함으로써 크게 3가지 형태로 제시되었다. 모의실험 결과 성능측면에서는 큐에 대해 개별적으로 임의 지연시간을 적용하였을 때 상대적으로 우월한 성능을 보였다. 또한 복잡도 측면에서는 채널에 대하여 집합적으로 임의 지연시간을 적용했을 때 상대적으로 낮은 복잡도를 보였다. 임의 지연시간을 분할된 채널에 대해 개별적으로 적용하는 방식은 성능과 연산복잡도의 trade-off관계에 있어서 앞서 제시된 방식들보다 우위에 있음을 보이고 있다.
이병석 ( Byoung Seok Lee ),강문일 ( Mun Il Kang ),정용운 ( Yong Un Chung ),이채용 ( Chai Yong Lee ),한동운 ( Dong Un Han ),위성환 ( Sung Hwan Wee ),윤소라 ( So Rah Yoon ),조재진 ( Jae Jin Cho ),강주원 ( Ju Won Kang ) 한국가축위생학회 2008 韓國家畜衛生學會誌 Vol.31 No.4
For screening the appropriate field diagnostic techniques to failure of passive immuno-globulin transfer(FPT) in Korean-indigenous calves, 258 sera was examined by spectino-photometry for total protein(TP) and globulin(Glo), sodium sulfate precipitation test(SSPT), zinc sulfate turbidity test(ZSTT), and single radial immunodiffusion test(sRID). All calves aged within 6-week old. Morbidity and mortality to various diseases, mainly including enteric and respiratory disorders, were 18.9%(49) and 4.2%(11), respectively. FPT was 27,9%(72/258) when the cutoff point of TP was 4.5g/㎗ and among them the morbidity and mortality were 27.9% and 6.9%, respectively. FPT was 29.1%(75/258) when the cutoff point of Glo was 2.0g/㎗ and among them the morbidity and mortality were 29.0% and 6.9%, respectively. FPT was 13.1%(34/258) when the cutoff point of SSPT was 1+ and among them the morbidity and mortality were 67.6% and 23.5%, respectively. FPT was 19.7%(51/258) when the cutoff point of IgG with sRID was 1,000 ㎎/㎗ and among them the morbidity and mortality were 41.1% and 11.7%, respectively. In addition, mean concentration of IgG with sRID tested was 2,150 ㎎/㎗ at 3-day old but 1,100 ㎎/㎗ at 9-days with 1,100㎎/㎗. The results of the study were suggested that SSPT for FPT was the relatively reliable and convinient method for evaluating the immune status of calves(P<0.05).
김대우,이병석,최진우,Kim Dae-Woo,Lee Byoung-Seok,Choe Jin-Woo 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.3b
매체공유기반 통신 시스템은 매체접근제어 과정에서 단말기의 채별 점유 제약 조건에 따라 크게 완전매체공유 시스템과 불완전매체 공유 시스템으로 구분할 수 있다 본 논문은 불완전매체공유 시스템의 매체접근제어기법의 개발을 위해 채널할당기법을 다루었다. 최적 채널할당기법은 채널할당 문제를 다중항목흐름(multi-commodity flow) 최대화 문제로 간주하고 선형 프로그래밍 문제를 유도하여 전역 최적해를 구한다. 또한 연산 복잡도를 낮추기 위한 대안으로 준최적 채널할당기법을 제안한다. 이 방식은 2단 iSLIP 채널할당기법과 순차적(sequential) 채널할당기법으로 구분하여 제안한다. 모의실험 결과 순차적 채널할당기법이 2단 iSLIP 채널할당기법 비해 상대적으로 낮은 연산 복잡도와 우월한 성능을 나타냄을 확인할 수 있었다. We define the incomplete medium sharing system as a multi-channel shared medium communication system where constraints are imposed to the set of channels that may be allocated to some transmitter-receiver node pairs. To derive a centralized MAC scheme of a incomplete medium sharing system, we address the problem of optimal channel allocation The optimal channel allocation problem is then translated into a max-flow problem in a multi-commodity flow graph, and it is shown that the optimal solution can then be obtained by solving a linear programming problem. In addition, two suboptimal channel allocation schemes are proposed to bring down the computational complexity to a practical/feasible level; (1) one is a modified iSLIP channel allocation scheme, (2) the other is sequential channel allocation scheme. From the results of a extensive set of numerical experiments, it is found that the suboptimal schemes evaluate channel utilization close to that of the optimal schemes while requiring much less amount of computation than the optimal scheme. In particular, the sequential channel allocation scheme is shown to achieve higher channel utilization with less computational complexity than . the modified iSLIP channel allocation scheme.
서승원(Seung Weon Seo),정현용(Hyun Yong Jeong),이승민(Seug Min Lee),이병석(Byoung Seok Lee),김진희(Jin Hee Kim),김남재(Nam Jae Kim),노승무(Seung Moo Rho),송규상(Kyu Sang Song),신경숙(Kyung Sook Shin),조준식(June Sik Cho) 대한내과학회 2001 대한내과학회지 Vol.60 No.4
N/A Background: In order to decide on a strategy of the treatment against gastric cancer, an accurate preoperative evaluation of the depth of tumor invasion is essential. We have studied the depth of invasion in early gastric cancer by endoscopic findings. Methods: The preoperative endoscopic diagnosis of the depth of invasion was compared with pathologic findings in a total of 108 cases with early gastric cancers (EGC) which were confirmed pathologically in resected specimen. Results: Of one hundred eight EGCs, forty-one were elevated type, others were flat-depressed type. There was no relationship between the depth of invasion and macroscopic type of EGC. All of the elevated typed EGCs were differentiated carcinoma. In the depressed typed EGCs, Forty-five percent was differentiated carcinoma and fifty-five percent was undifferentiated carcinoma. The incidence of lymphnode metastasis in submucosal cancers (14.8%) was significantly more than in mucosal cancers (1.6%). Among the submucosal cancers, the incidence of nodal metastasis in double lesions (100%) was significantly more than in single lesions (14.8%). In the elevated typed EGCs, mucosal cancers were small in size less than 3.0 cm (83%), and contained whitish patches, and showed uneveness and erosion. Submucosal cancers were large in size, and contained ulcers, and showed submucosal tumor-like shapes and bridging folds. In the depressed typed EGCs, it was difficult to determine endoscopically the depth of invasion. Submucosal cancers showed the fusion of converging folds and unevenness of the depressed base. The regularity of the depressed base without ulcer was primarily found in mucosal cancer. Conclusion: When the tumor was elevated, the endoscopic diagnosis for the depth of invasion was determined easily by size of the lesion and features of the elevated surface. For the depressed tumor, diagnostic clues were the pattern of the base of the depression and the converging fold, and the endoscopic diagnosis of the depth of invasion was much more difficult than the elevated type EGC.(Korean J Med 60:330- 336, 2001)
은나노 입자의 입경 크기 및 형태에 따른 체내 동태 및 염증 반응
김수남(Soo Nam Kim),노진규(Jinkyu Roh),강민성(Min Sung Kang),한영아(Young-Ah Han),이병석(Byoung-Seok Lee),김영훈(Younghun Kim),박광식(Kwangsik Park),최경희(Kyunghee Choi),박은정(Eun-Jung Park) 환경독성보건학회 2010 환경독성보건학회지 Vol.25 No.3
The market size of engineered nanoparticles is rapidly increasing due to the fast application of nanotechnolo-gies into different industries and consumer products. The development of new technology and materials has improved human's quality of life, but it also entails the possibility of exposure to new materials. In this study, we compared the distribution in the body by the inflow of silver nanoparticles having another diameter and shape at 1 h or 24 h after injection via the tail vein. And, we compared the cell composition and cytokine concentration in SAL fluid, and histopathological changes. As results, discharge of silver nanoparticles having small diameter and sphere shape was more rapid than that of big diameter or plate shape. It is estimated that the toxicity in liver and lung was proportional to accumulation level. The persistence of inflammation was also longer in mice treated with plate shape. Consequently, we suggest that the first choice of silver nanoparticles having small diameter and sphere shape in applying is desirable.