• Journal of Korean Neurosurgical Society
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• 제46권5호
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• pp.484-487
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• 2009

It is not uncommon for hemangiomas to occur in the calvarium, accounting for about 10% of the benign skull tumors. A 46-year-old man was presented with a palpable scalp mass on the left parietal region. Past medical history indicated that he had undergone cranioplasty 25 years prior due to a depressed skull fracture suffered from a traffic accident. Magnetic resonance imaging revealed mixed signal intensity mass on T1 -and T2- weighted images pushing a linear signal void lesion outward in the left parietal region. After total surgical removal along with cranioplasty, he was discharged without neurological deficits. Histological examination of the surgical specimen revealed a cavernous hemangioma. A skull hemangioma occurring at the site of a cranioplasty has not yet been reported. Therefore, authors report this case in combination with a pertinent literature review.

• 산업공학
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• 제25권4호
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• pp.431-440
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• 2012

Since pooling is a popular scheme in many areas to attain operational excellence, many researchers investigated the performance of pooling systems. However, rare research could be found on pooling with game situation which has much applicability to real world phenomenon. We analyze the performance of noncooperative pooling system with two servers having different sharing capacity. We investigate the sensitivity of the advantage of capacity pooling on the variation of system parameters, including sharing capacity numbers, pooling probability, pooling strategy and traffic intensity. As a result, we suggest an efficient control policy which facilitate the performance of pooling in a game situation.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.633-636
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• 2004

Airborne laser scanning thechnology has been studied in many applications, DSM(Digital Surface Model) development, building extraction, 3D virtual city modeling. In this paper, we will evaluate the possibility of airborne laser scanning technology for transportation application, especially for recognizing moving vehicles on road. First, we initially segment the region of roads from all LiDAR DATA using the GIS map and intensity image. Secondly, the segmented region is divided into the roads and vehicles using the height threshold value of local based window. Finally, the vehicles will be classified into the several types of vehicles by MDC(Minimum Distance Classification) method using the vehicle's geometry information, height, length, width, etc

• 건축역사연구
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• 제7권4호
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• pp.9-27
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• 1998

The urban form of Korean cities significantly changed in the late Chosun dynasty. The influence of commercial development was the main cause of these changes. Commerce became a important function of existing cities, and the new type of commercial towns emerged at the important spots of traffic routes. In both cases streets became dominant element of urban form. Mainly commercial buildings aggregated along the streets, and to obtain higher land use intensity shape of lots became narrow and deep. Koyang(高陽) shows the most significant example of this new type of lot and lot pattern. Approximately 30 narrow and deep type of lots lined on each side of street forming about 390 meters long linear commercial town. Similar examples were found at the outside of south gate of Suwon(水原), Nuwon(樓院), and Pangyo(板橋).

• 대한산업공학회지
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• 제7권1호
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• pp.5-11
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• 1981

In the case of numerical implementation, the exact solution method for the M/M/s system where customers demand multiple server use [2] reveals limitations, if a system has large number of servers or types of customers. This is due to the huge matrices involved in the course of the calculations. This paper offers an approximation scheme for such cases. Capitalizing the characteristics of the service rate curve of the system, this method approximates the service rate as a piecewise linear function. With the service rates obtained from the linear function for each number of customers n (n=0. 1. 2,$\cdots$), ${\mu}(n)$, steady-state probabilities and measures of performance are found treating this system as an ordinary M/M/s system. This scheme performs well when the traffic intensity of a system is below about 0.8. Some numerical examples are presented.

• 한국안전학회지
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• 제10권4호
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• pp.109-117
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• 1995

본 논문은 야간 운전자들의 안전을 위한 교통안전제어 시설체계인 주행안내 반사체시스템(Retroreflector)에 있어서 기하도형각과 명확도 사이에 성량 변형이 등가적인 새로운 이론적 설계에 의한 다체형 회전체의 전환 모형에 관한 연구이다. 야간운전자의 주행안내 반사체 성능과 운전자 환경을 고려하여 이론적으로 동질적인 다섯가지 모형을 검증한다. 이 모형은 주행안내 반사체 교통체계를 설계하는데 좀더 나은 운전성과, 안전, 그리고 경제성 등을 고려하여 평가할 수 있을 것이다.

• International Journal of Railway
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• 제5권2호
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• pp.71-76
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• 2012

Recently, axle load, operating speed and traffic density on railroads have had a tendency to increase and thereby cause additional pressure applied on used track. These operating conditions frequently result in service failure due to wear caused by wheel-rail contact and fatigue damage under cyclic loading. Among rail defects, the transverse crack, which has been the most dangerous type of fatigue damages, is developed from the subsurface crack near the rail running face and grows perpendicular to the rail surface. Therefore, it is necessary to investigate systematically the growth behavior of transverse crack for rail steel under mixed mode. In this study, the fatigue crack growth behavior of the transverse crack in rail steel was experimentally investigated under mixed-mode variable amplitude loadings.

• 한국경영과학회지
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• 제25권2호
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• pp.59-66
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• 2000

In this paper we propose an approximation analysis for the system size distribution of the M/G/c system which is transform-free,. At first we borrow the system size distribution from the Markovian service models and then introduce a newly defined parameter in place of traffic intensity. In this step we find the distribution of the number of customers up to c. Next we concentrate on each waiting space of the queue separately rather than consider the entire queue as a whole. Then according to the system state of the arrival epoch we induce the probability distribution of the system size recursively. We discuss the effectiveness of this approximation method by comparing with simulation for the mean system size.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2010년도 추계학술대회
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• pp.139-140
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• 2010

This paper presents an indoor prototype for wireless digital signal transmission using Visible Light Communications (VLC) in which high power Light Emitting Diode (LED) is used. Using low cost and off-the-shelf components, the transmitter module is constructed using an AVR Atmega128 microcontroller and commercial white beam LEDs. Modulating the light intensity of the LED enables digital signals to be transmitted across the optical link. The receiver module employs a high speed PIN photodetector for optical signal detection and a recovery circuit for optical-electro signal conversion. By sending digitalized data via VLC technology, many applications can be realized in the areas of consumer advertising, traffic safety information and disaster control.

• International Journal of Internet, Broadcasting and Communication
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• 제15권1호
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• pp.1-7
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• 2023

TCP is considered a major candidate transport protocol even for constrained IoT networks due to its ability to integrate into the existing network infrastructures. Since TCP implementations such as uIP TCP often allow only a single TCP segment per connection to be unacknowledged at any given time due to resource constraints, the congestion control relies only on RTO management. In our previous work, to address the problem that uIP TCP performs poorly particularly when a radio duty cycling mechanism is enabled and the hidden terminal problem is severe, we proposed a RTO scheme for uIP TCP and validated the performance through Cooja simulation. In this study, we investigate the effect of other factors that were not considered in our previous work. More specifically, the effect of traffic intensity, the degree of the hidden terminal problem, and RDC is investigated by varying the offered load and the transmission range, and the RDC channel check rate. Simulation results imply that we need to further investigate how to improve TCP performance when the radio duty cycling mechanism is used.