• 한국통신학회논문지
• /
• 제40권10호
• /
• pp.1986-1993
• /
• 2015

본 논문에서는 다중 셀 셀룰러 네트워크에서 단말 간 직접 통신(Device-to-Device: D2D)의 성능을 최대화하기 위한 최적 자원 및 전력 할당 알고리즘을 제안한다. 셀룰러 단말과 D2D 단말이 통신 자원을 공유하는 상황에서 필연적으로 D2D 단말은 자신이 속한 셀뿐만 아니라 인접한 셀의 D2D 단말과 셀룰러 단말로부터 간섭을 받게 된다. 이러한 환경에서 셀 내의 간섭과 인접 셀의 간섭을 고려한 인집 기지국간의 협력적 D2D 자원 할당 방법을 제안한다. 또한 자원 할당이 이루어진 후 D2D 단말의 최적 전력 할당 문제를 제시하고 최적해를 찾는 알고리즘을 제시한다. 제안하는 D2D 자원 및 전력 할당 알고리즘은 셀룰러 단말의 성능을 보장하기 위해 D2D 단말의 송신전력 제약 조건을 갖는 상황에서 셀룰러 단말로부터의 간섭과 인접 셀 D2D 단말로부터의 간섭을 고려하여 D2D 단말이 얻을 수 있는 전송률을 최대화시킬 수 있다. 다중 셀 환경에서의 모의실험을 통하여 제안한 자원 및 전력 할당 알고리즘의 성능을 검증하고 기존의 비협력적 자원 할당 방식과 비교하여 제안한 협력적 자원 할당 방식의 성능 이득을 확인한다.

• International Journal of Computer Science & Network Security
• /
• 제22권6호
• /
• pp.275-287
• /
• 2022

As a result, for the increasing expansion by the university faculties in the field of postgraduate studies, The Deanship of Graduate Studies at the university has been established in 1430 AH/2009 CE to specifically address the needs of the current and prospective graduate population to supervise postgraduate studies programs in coordination with the concerned faculties. This comes as a result for the university being certain of the importance of providing postgraduate studies opportunities that follow the bachelor's degree to qualify our ambitious youth appropriately. The University offers 72 different Graduate programs, awarding doctoral and master's degrees along with fellowships and diplomas in various disciplines like health, engineering, science, literary, and educational. Currently, the financial model for admission and students' payment is manual and paper based. This paper proposes to provide a user interface for Financial Management in Deanship of Graduate studies The basic purpose of the system was to minimize human interference and reduce mistakes placed by human interference, also to have efficient and a fast performance, and perform Electronic Data Interchange (EDI) for various tasks such as billing and scheduling details.

• Journal of Communications and Networks
• /
• 제12권5호
• /
• pp.449-458
• /
• 2010

In this paper, we present a distributed resource allocation algorithm for multi-cell uplink systems that increases the weighted sum of the average data rates over the entire network under the average transmit power constraint of each mobile station. For the distributed operation, we arrange each base station (BS) to allocate the resource such that its own utility gets maximized in a noncooperative way. We define the utility such that it incorporates both the weighted sum of the average rates in each cell and the induced interference to other cells, which helps to instigate implicit cooperation among the cells. Since the data rates of different cells are coupled through inter-cell interferences, the resource allocation taken by each BS evolves over iterations. We establish that the resource allocation converges to a unique fixed point under reasonable assumptions. We demonstrate through computer simulations that the proposed algorithm can improve the weighted sum of the average rates substantially without requiring any coordination among the base stations.

• 한국인터넷방송통신학회논문지
• /
• 제8권4호
• /
• pp.35-42
• /
• 2008

DCF 성능 분석 모델에 사용되는 Bianchi의 2차원 Markov Chain 모델은 오류가 없는 이상적 채널에서 충돌 문제만을 다루므로 페이딩, 간섭, 잡음 등 실제 채널의 특성을 반영하지 못한다. 802.11 DCF는 전송실패가 충돌에 의한 것이든, 채널 전송오류에 의한 것이든 경쟁윈도우(CW) 크기를 두 배로 증가시키는 2진 지수후퇴 알고리즘을 작동시킨다. 이상적으로 경쟁윈도우 증가는 혼잡에 의한 충돌방지 때에만 사용되어져야 한다. 통신오류에 의한 경쟁윈도우 증가는 데이터 처리율을 떨어뜨리고 전송지연의 증가를 야기 시킨다. 오류 채널에서는 전송실패 증가가 과도한 이진 지수후퇴를 야기하므로 초기 경쟁윈도우(CW) 크기를 줄여줄 필요가 있다. 본 논문에서는 경쟁윈도우(CW), 타임슬롯에서 전송 확률(${\Im}$), 전송 실패 확률($p_f$) 등이 시스템 성능에 미치는 영향을 정량적, 정성적으로 분석을 하고 등가적으로 CW 값을 얼마큼 줄여야 할지를 제시한다.

• 한국염색가공학회지
• /
• 제27권4호
• /
• pp.261-269
• /
• 2015

Two new D-${\pi}$-A dyes were synthesized by the condensation reaction between active methyl and aromatic aldehyde and its biothiol sensing properties in DMSO/water were investigated by UV-vis spectroscopy. Upon addition of $Hg^{2+}$, the solution of D-${\pi}$-A dyes showed color change and the absorption band shows a formation of a dye-$Hg^{2+}$ coordination complex. These dyes exhibited high selectivity for $Hg^{2+}$ as compared with other cations. The dye-$Hg^{2+}$ could be recovered by adding glutathion(GSH). The absorption intensity of dye-$Hg^{2+}$ increased only by the addition of glutathione(GSH). The competition experiments revealed that no obvious interference was observed by performing the titration with the mixture of glutathione(GSH) and other amino acids. The results indicated that these D-${\pi}$-A dyes were highly selective for glutathione(GSH) detection.

• Journal of Korean Neurosurgical Society
• /
• 제47권3호
• /
• pp.191-198
• /
• 2010

Objective : This study is planned to determine the neurocognitive difficulties of hydrocephalic adults. Methods : The research group contained healthy adults (control group, n : 15), and hydrocephalic adults (n : 15). Hydrocephalic group consisted of patients with idiopathic aquaduct stenosis and post-meningitis hydrocephalus. All patients were followed with shunted hydrocephalus and not gone to shunt revision during last two years. They were chosen from either asymptomatic or had only minor symptoms without motor and sensorineural deficit. A neuropsychological test battery (Raven Standart Progressive Matrices, Bender-Gestalt Test, Cancellation Test, Clock Drawing Test, Facial Recognition Test, Line Orientation Test, Serial Digit Learning Test, Stroop Color Word Interference Test-TBAG Form, Verbal Fluency Test, Verbal Fluency Test, Visual-Aural Digit Span Test-B) was applied to all groups. Results : Neuropsychological assessment of hydrocephalic patients demonstrated that they had poor performance on visual, semantic and working memory, visuoconstructive and frontal functions, reading, attention, motor coordination and executive function of parietal lobe which related with complex and perseverative behaviour. Eventually, these patients had significant impairment on the neurocognitive functions of their frontal, parietal and temporal lobes. On the other hand, the statistical analyses performed on demographic data showed that the aetiology of the hydrocephalus, age, sex and localization of the shunt (frontal or posterior parietal) did not affect the test results. Conclusion : This prospective study showed that adult patients with hydrocephalus have serious neuropsychological problems which might be directly caused by the hydrocephalus; and these problems may cause serious adaptive difficulties in their social, cultural, behavioral and academic life.

• 한국멀티미디어학회논문지
• /
• 제24권8호
• /
• pp.1138-1148
• /
• 2021

In this study, we developed a 'shared-use mobility'-mounted local particulate matter monitoring terminal technology to measure the actual particulate matter concentration around me. As a mobile terminal device in the form of an IoT sensor platform, it is designed to be separated into a control module and a sensor module to minimize interference between sensors and to consider the optimal observation position of each sensor. As a result of the field test, it was confirmed that particulate matter was locally different depending on time and space even within the same area. In addition, it was confirmed that the concentration of particulate matter in the relevant section differed by up to 100 times compared to the surrounding area due to specific sources of particulate matter such as unpaved roads. In addition, we positively reviewed the applicability of the service in the real-time metaverse environment using this result. Through technological advancement and application of multiple shared-use mobilities, we expect to be able to provide new services for practical smart city air environment monitoring, such as localized particulate matter information, air pollution event information, and identification of causes of particulate matter.

• 대한전자공학회논문지TC
• /
• 제43권10호
• /
• pp.79-89
• /
• 2006

TCP는 신뢰성을 보장하는 전송 프로토콜로서 인터넷 등에서 가장 널리 사용되고 있는 전송 방식이다. 하지만 TCP는 유선망에 적합하도록 설계되었기 때문에 무선망에서 TCP를 사용할 경우 성능 저하가 발생된다. TCP의 성능 저하 원인으로는 MAC 계층에서의 무선 매체 경쟁, hidden-terminal 문제와 exposed terminal 문제, 링크 계층에서의 패킷 손실, 불공정성의 문제들과 노드의 이동에 의한 경로 단절시 발생되는 패킷 순서 바뀜 문제와 경로의 단절로 인한 재전송 타이머의 exponential backoff에 의한 대역폭의 낭비 등이 있다. 특히 이동 ad-hoc 망에서는 전송 범위(transmission range)와 간섭범위(interference range)의 불일치로 인해 발생되는 hidden terminal 문제로 인해 동시에 전송할 수 있는 노드의 수가 제한되며 이로 인해 성능저하가 크게 발생된다. 본 논문에서는 IEEE 802.11 기반 이동 ad-hoc 망에서 발생되는 hidden terminal 문제로 인해 노드가 전송을 하지 못하고 CW(contention window)만 크게 증가되는 문제를 해결하기 위한 MAC 알고리즘을 제안한다. 기존의 802.11 MAC의 DCF(distributed coordination function)에서는 전송에 실패할 경우 CW를 지수적으로 증가시키지만 본 논문에서 제안하는 기법은 노드가 전송 실패를 하였을 경우 그 원인에 따라 CW를 적절하게 변화시킴으로 성능 향상을 얻을 수 있다. 이 기법을 사용하면 hidden terminal에 의해 전송을 실패하는 노드에게 공정한 전송 기회를 부여함으로써 TCP 성능 향상을 얻을 수 있음을 시뮬레이션을 통해 보였다.

• Journal of Oral Medicine and Pain
• /
• 제13권1호
• /
• pp.23-33
• /
• 1988

The purpose of this study was to standardized and classify the coordination pattern among the chewing side and non-chewing side masseter and anterior muscles, in terms of EMG values on lateral excursion, clenching, and mastication in presence of the non-chewing side. In this study, 25 subjects were selected for experiment of lateral excursion, clenching and mastication and EMG value of the masseter and anterior temporal muscle on both sides were recored 2 times respectively. The bioelectric processor model EM2(Myo-tonic research, INC. U.S.A.) with the surface electrodes were used to record the EMG activity during all experimental procedures. The results were as follows : 1. During lateral excursion on intereference of non-chewing side, the EMG values of the temporal muscle were significantly more prominent than those of the temporal muscle on the non-chewing side. The EMG values of non-chewing side were significantly more prominent than those of chewing side on the both side masseter muscle and those of chewing side were significantly more prominent than those of non-chewing side on the both side temporal muscle. 2. During clenching on the occlusal interferance, the EMG values of non-chewing side masseter muscle were most prominent. 3. During mastication on the occlusal interferance, the EMG values of the chewing side temporal muscle were most prominent and those of non-chewing side temporal muscle were the lowest. 4. The EMG values of temporal muscle of non-chewing side on interferance were significantly more prominent than those of canine guidance during lateral excursion. 5. During clenching on the occlusal interferance, the EMG values of the masseter and the temporal muscles of the non-chewing side were significantly more prominent than canine guidance, but those of chewing side temporal muscle on canine guidance were significantly more prominent than those of interferance. 6. During mastication on canine guidance, the EMG Values of the temporal muscle on the chewing side, the masseter muscle on the chewing side and the temporal muscle on the non-chewing side were more prominent than those of interferance, but temporal muscle of non-chewing side was not different between canine guidance and occlusal interferance on non-chewing side.

• 대한교통학회:학술대회논문집
• /
• 대한교통학회 1995년도 한-중 국제학술회의 발표논문
• /
• pp.239-250
• /
• 1995

With speeding up the process of being international municipality, the gravity of lacking parking lots in Shanghai urban area, which directly blocks the traffic in the city, has been revealed. This thesis analyses present automobiles parking capability and forecasts the future's needs for the city. To solve the problem, the concept could be to expand parking areas in city center recently to relax the tention and to do thoughtful planning in the near future on the foundation of fully consideration the trend. The municipal government has to set up policy properly, amplify regulations, strenthern the administration and open up a path to raise founds. Berween road system administration which is dynamic and parking lot system administration which is static, there are a knot on macroscopic meaning and an interference as well. The coordination of these two systems would be reflested on the effects of whole municipal traffic adminisration. Basically, public parking lots are city's foundal facilities, just like roads, bridges, etc. The main problems now in Shanghai are large parking space demands, insufficient facilities, cheap parking expenses comparing with the cost of parking lots construcion and poor administration. According to the forecast on social economy development, there will be 580 thousand automobiles in Shanghai by the year 2000, and the amount of private cars will increase greatly. The frequency of automobiles going out will be 1.45 million per day. Public parking lots being able to afford 105 thousand units are needed. To satisfy the demands, the recent aim of planning should be speed up the parking lots construction, the planning objective in next period should be developing reasonably and exceed the demands properly. In order to realize the planning objective, the government has to formulate correct policy and amplify administration regulations. The government has to adopt both administration and economy means, including charging parking people reasonably, collect necessary taxes, bringing the parking lots planning into general municipality planning, opening up an effective path to raise founds, such as set up founds for parking lots construction, issue bonds and stocks, get loans at home and abroad, etc.