Earticle

This research intends to improve the method of allocating crime prevention facilities in a residential district. Authors tried to calculate running speed of female youth as a means to measure distance to reach crime prevention facilities. In order to overcome conventional method of two dimensional buffer analysis, authors suggested new method of buffer analysis by considering gradient and refraction. Buffer areas for both conventional and new approach are compared after constructing GIS model of the site in Yeomri-dong, Mapo-gu, Seoul. The result shows that buffer area of crime prevention facilities drawn from conventional method (i.e. not considering gradient and refraction) covers 74.7%, whereas the area drawn from improved method (i.e. considering gradient and refraction) covers only 38.4% of the road within the site. The result indicates that conventional method of allocating crime prevention facilities does not guarantee safety of female youth in a steepy and bended alley. Therefore, when providing design guidelines for crime prevention facilities, it is necessary to apply the improved method considering gradient and refraction of the road.

본 연구에서는 심해저 광물자원 개발을 위해 사용되는 양광시스템에서 버퍼시스템을 설계하고 전산해석을수행하였다. 저장탱크와 유연관 및 출구관을 가지는 버퍼시스템 격자모델을 형성화하였고 버퍼시스템 내에서의 망간단괴와 해수의 유동을 해석하였다. 유연관로부터 저장탱크로 유입된 유체는 압력이 감소되면서 좌우 대칭의 순환류가 발생하였고 출구관을 통해 배출되면서 압력이 상승하였다. 이러한 결과는 버퍼시스템 설계제작에서 중요한 사실을 제공한다. 먼저, 탱크 내에서의 순환유동은 압력손실로 이어지기 때문에 이러한 주 유동을 축소하거나 제거할수 있는 탱크의 설계가 필요하다. 또한 출구관에서의 압력손실은 벽면과의 마찰로 의한 에너지 손실 때문에 발생되며이는 유동속도가 감소시키고 궁극적으로 망간단괴의 유동을 방해하므로 실제 탱크제작 및 현장가동 시에는 이러한문제요소들을 반영하여 설계해야 한다.

In this study buffer system was designed for the development of the lifting system of deep-sea mineral resources, and computational fluid dynamic(CFD) simulation was performed. Firstly, grid model of buffer system having storage tank, flexible hoses, and outlet pipes were made. Then simulations of pressure and velocity distribution were conducted according to fluid flow in the buffer system. The mixture fluid from flexible hoses to the storage tank shows symmetrically circulating flow pattern with pressure drop and the pressure rises again at the exit of the tank. The results present important facts for manufacturing a buffer system. Design of tank will be required to reduce or remove circulation due to pressure loss by circulation flow in tank. Pressure loss from outlet pipe is caused due to energy loss by wall friction, and it will reduce flow velocity and disturb flow of manganese nodules.

As vehicle technology becomes advanced, the vehicle ride quality is improved. Safety of automotive suspension system is influenced directly with quality ride of passenger. This study aims at the improvement of automotive shock absorbers. Static and vibration analyses are analyzed at car cushion buffer with spring force due to the weight movement of vehicle. The maximum equivalent stresses and strains are calculated and six different natural frequencies are applied with each mode of vibration. Maximum deformation vibration value is also derived by the condition of harmonic vibration. As the durability of advanced automotive shock absorber can be improved by applying this study result with the design of car cushion buffer. ride quality gets better and the damage can be prevented.

In order to solve the efficiency of buffer analysis of line elements, adopt plane graph model and according to the characteristic of simple feature model, making the bounding-edges of the line elements into plane graph model, then According to certain rules to filter the lines of plane graph model to gain the bounding edges of buffer and then gain the results. In this algorithm, firstly, As required, do parallel lines and polylines vertex processing for the line elements extracted from the objects which need buffer analysis , and gain the Intermediate line objects, then Generate line elements of graph model through computing intersecting points and clip lines using static R tree index, Moreover using the multiple programming standard OPENMP, Optimize the parallelism of every step of the vector buffer analysis algorithm, This algorithm can solve buffer efficient of large data and it’s is better than other algorithm in physical problem.

The damage of cylinder and equipment due to the pile detaching can be avoided by using the buffer device with large flow, which adopts throttle buffer inside the cylinder combining with the control of the relief valve outside the cylinder. To investigate the thermodynamic characteristics of the cylinder chambers and the law of movement of piston, the accurate mathematic model need to be established so the method based on pseudo-bond graph is introduced. According to the conservation equations for mass and energy, the thermal-hydraulic pseudo bond graph C and R elements are developed, and the connection rule for the two elements are determined based on their input and output variables. The bond graph model of the buffer system containing the coupled of multiple energy domains is obtained in a unified way based on the structure and working principle of buffer device, then the system state equations have been derived from the model. The model can be used in variable parameters’ simulation with the parameters in the experiment, the pressure simulation data of two chambers of impact cylinder agree well with the experimental results, which indicate that the model can be used for the design and optimization of buffer device of hydraulic pile hammer.

In this study, the efficiency by storage medium according to changes in the buffer size was compared and analyzed focusing on parameters setting the size of the buffer that most of DBMSs have in common in relation to storage media. efficiency was compared and analyzed by NBD(NHN Bulletin Board Application Database) according changes to the buffer size when single load which different work load from that of the TPC-H model. It was observed In QUIBRID that there is a difference due to the performance of the two storage media when TPS has been measured by giving single or multi-load through Level 2 of the NBD Benchmark but that there is no change in TPS according to the buffer size. It is because the small loads of Level 2 are processed within a range of not exceeding the buffer capacity. Thus it appears that for small loads for reading, printing out, or searching posts, there is no need to apply the large buffer to the two storage media all. D-SSD show no performance degradation due to excellent Read/Write functions. Thus, it is expected to achieve the desired performance without tuning works on the buffer size to process DB data.

Most of the present DMBSs have parameters to set the size of data buffer caching in a memory, and disc I/O can be reduced, as the buffer size is greatly reduced, because data pages caching in a buffer increase. Whereas greatly setting this parameter value makes a memory occupy a system excessively, and the buffer pool may be swapped by system's operating system.This article compared and analyzed efficiency of each storage medium, by changing the size of data buffer caching in a memory, after connecting DBMS with a storage medium. According to the result of the test, both performances of storage media increased, as the buffer size was greatly reduced. Seeing that D-SSD's performance and HDD's performance changed from above 1GB and 2GB, respectively, it is supposed that there is no need to cut down the buffer size infinitely, because performance doesn't change from a certain section, although it improves, as the buffer size highly decreases. It isn't necessary to expand the buffer size greatly under the small load, since there was no change of performance, even when the buffer size was greatly increased under the small load. While D-SSD also can maintain its performance without any big change, if it exceeds the scope of capacity that the buffer can process, HDD shows a considerable reduction of performance. Therefore, it is likely that unlike HDD, for D-SSD, tuning the buffer size isn't needed. However, there is a need of conducting a test in an actual service environment in future, because these results came from the test in a single server.

Regardless that the classic buffer overflow is a known and simple threat against software systems; security agencies still consider this threat as one of the most common software vulnerabilities. Aiming to increasing security resistance against this software threat, emphasize on software design phase is highly reasonable where cost and time required for fixing error in design level is several times lesser than coding or implementation levels. In this purpose, we use the Attack-based security analysis model for tracking and mitigating the classic buffer overflow during the software design phase. Through this model, we use known properties and behaviors of the buffer overflow to determine system vulnerabilities and address required security aspects. In this paper, we describe how to apply the Attack-based security analysis model for increasing security resistance against the classic buffer overflow. The main contribution of this work refers to showing capability of the Attack-based security analysis model in tracking and mitigating the classic buffer overflow into the software design phase in such a way that additional cost and time are not required for system analyzing and defining threat scenario.

Network on chip (NoC) is an emerging technology in the field of multi core interconnection architecture. The routers plays an essential components of Network on chip and responsible for packet delivery by selecting shortest path between source and destination. State-of-the-art NoC designs used routing table to find the shortest path and supports four ports for packet transfer, which consume high power consumption and degrades the system performance. In this paper, the multi port multi core router architecture is proposed to reduce the power consumption and increasing the throughput of the system. The shared buffer is employed between the multi ports of the router architecture. The performance of the proposed router is analyzed in terms of power and current consumption with conventional methods. The proposed system uses Modelsim software for simulation purposes and Xilinx Project Navigator for synthesis purposes. The proposed architecture consumes 31 mW on CPLD XC2C64A processor.

This study is intended to analyze the requirements of a buffer material that is one of the major components of the engineered barriers in a high-level radioactive waste repository. The characteristics of potential materials for the buffer in the repository were analyzed and a candidate material was selected. And, based on the current knowledge and the information from various sources, the requirements of a buffer material were evaluated. Finally its quantitative functional criteria on the generic viewpoint has been recommended to be supplied as a guideline for the development of the reference disposal concept and the related buffer material in Korea. The criteria are composed of seven major items, such as hydraulic conductivity, retardation capacity, swelling potential and swelling pressure, thermal conductivity, longevity, organic matter content, and mechanical properties.

수소 추출과 리포밍 과정, 연료 전지, 저장소로 구성된 수소 연료에 대한 연구는 세계적으로 번영하고 있는 중이다. 그러나 한국의 수소 스테이션에 대한 연구는 아직도 개발이 미미한 수준이다. 그리고 역시 수소 스테이션의 가장 중요한 부분인 수소 압축기에 대한 연구도 미흡하다. 수소압축기에서 가장 중요한 부분 중에 하나는 스너버인데 이것의 기능은 수소가스의 맥동압을 줄이고 불순물을 제거한다. 스너버 내부에는 버퍼라고 불리는 기울어진 판이 설치되어 맥동압을 줄이고 불순물을 제거하는 역할을 담당한다. 스너버 내부의 압력 손실과 맥동압이 최소가 될 때 스너버는 적절한 성능을 가졌다고 평가된다. 그러므로 이 연구의 목적은 수치해석을 통하여 스너버의 최적의 기하학적 크기와 버퍼의 각도에 따른 최적의 스너버를 찾는 것이다. 수치해석의 결과에서 다양한 버퍼각도에 따른 스너버의 독특한 특성을 볼 수 있다. 결과적으로 버퍼의 각도가 $35^{\circ}$일때 최소의 압력손실율이 발생했고, 버퍼의 각도가 $10^{\circ}$일 때 최소의 맥동압이 발생하였다.

Recently, the use of an aluminum nitride(AlN) buffer layer has been actively studied for fabricating a high quality gallium nitride(GaN) template for high efficiency Light Emitting Diode(LED) production. We confirmed that AlN deposition after $N_2$ plasma treatment of the substrate has a positive influence on GaN epitaxial growth. In this study, $N_2$ plasma treatment was performed on a commercial patterned sapphire substrate by RF magnetron sputtering equipment. GaN was grown by metal organic chemical vapor deposition(MOCVD). The surface treated with $N_2$ plasma was analyzed by x-ray photoelectron spectroscopy(XPS) to determine the binding energy. The XPS results indicated the surface was changed from $Al_2O_3$ to AlN and AlON, and we confirmed that the thickness of the pretreated layer was about 1 nm using high resolution transmission electron microscopy(HR-TEM). The AlN buffer layer deposited on the grown pretreated layer had lower crystallinity than the as-treated PSS. Therefore, the surface $N_2$ plasma treatment on PSS resulted in a reduction in the crystallinity of the AlN buffer layer, which can improve the epitaxial growth quality of the GaN template.

We propose a current mode logic circuit design method for LTPS TFT for enhancing circuit operating speed. Current mode inverter/buffers with passive resistive load had been designed and fabricated. Measurement results indicated that the smaller logic swing of the current mode allowed significantly faster operation than the static CMOS. In order to reduce the chip size, both all pTFT and all nTFT active load current mode inverter/buffer had been designed and analyzed by HSPICE simulation. Even though the active load current mode circuits were inferior to the passive load circuits, it was superior to static CMOS gates.

This paper investigates the cyclical patterns of buffer capital using an unbalanced panel data for the banks in 30 OECD countries and 7 non-OECD Asian countries. We test whether the relationships between buffer capital and business cycle are systematically different across country groups controlling for other potential determinants of bank capital. We find that the correlation is positive for developed countries while it is negative for Asian developing countries. These findings suggest that, once Basel II is implemented, developing countries are more likely to observe an increase in output volatility. We then review the policy recommendations to mitigate the procyclicality problem of Basel II.

본 논문에서는 ATM 망과 FR(Frame Relay) 망간의 연동장치(IWU)에서 ATM 망으로부터 프레임 셀들을 수신하여 프레임으로 복원한 후 FR 망으로 전송하는 프레임 셀 수신 버퍼의 소요량을 분석하였다. 이 프레임 셀 수신 버퍼에는 ATM 망을 통하여 다수의 다른 FR 망들로부터의 프레임 셀들이 다중화되어 입력된다. 수신되는 셀들은 VPI/VCI별로 동시에 프레임으로 조립되고, 프레임이 완성되면 각 연결의 설정에 따라 여러 개의 FR 망 전송 링크들 중 하나로 전송용량에 따라 순차적으로 전송된다. 따라서, IWU의 셀 수신부에는 다중화된 프레임 셀들을 VPI/VCI별로 동시에 프레임으로 조립하기 위한, 또한, 조립이 완성된 프레임에 대해서는 FR 링크로 전송되기까지 대기할 충분한 버퍼가 필요하다. 본 논문에서는 프레임 셀 수신버퍼에 입력되는 트래픽 및 버퍼를 모델링하고 입력되는 트래픽의 파라미터들, 다중화 FR 연결의 수 및 FR 출력 링크의 수 및 전송능력 등의 항으로 프레임 손실 확률을 유도하였다. 이 손실 확률에 따라 주어진 손실 확률을 만족하는 소요 버퍼량을 여러 가지 연동 환경을 가정하여 분석하고 제시하였다. 또한, FR 연결의 다중화 수, 출력 링크의 수에 따른 손실율 및 버퍼 소요량의 변화 등을 분석하여 제시하였다.

In this paper, the size of IWU frame cell buffer is analyzed that receives FR frame cells from other FR networks through ATM backbone network. The frame cell buffer receives multiplexed ATM cells from other IWUs that provide interworking with ATM network for other FR networks A receiving IWU reassembles frames from multiplexed ATM cells by identifying the VPI/VCIs. The reassembled frames are transmitted on FR network links according to their destination. Therefore, IWU needs sufficient amount of buffers for the assembly of the frames and for providing the assembled frames with the queue to wait until the frame is transmitted by FR network link. In this paper, the probability of frame loss at the frame cell buffer is derived in terms of traffic parameters, the number of multiplexed FR connections, the number of FR links and the transmission capacity. By applying the derived results, we analyzed the required buffer size for a given probability of frame loss. Also, it is presented that how the probability and the required size are effected by the number of multiplexed FR connections and FR transmission links.

In this work, Organic Light Emitting Diodes using LiF as a electron-injecting interfacial have been fabricated for efficiency enhancements. This interfacial layer is interposed between Al/$Alq_3$ layer. The brightness and specific character as current density are higher than those of the device without it. To find best thickness of LiF layer, we used some samples with various thickness. The LiF interposition at the Al/$Alq_3$ interface encouraged the electrons injection and balances the injection numbers of hole and electron in the emission layer.

3GPP2 방식에서는 Macro Mobility 지원을 위하여 MIP를 이용하며 PDSN은 FA의 기능을 수행한다. PDSN 관리 영역 내의 하나의 RN에서 다른 RN으로 이동시에 지원되는 이동성을 Micro Mobility라 한다. Micro Mobility에서 Seamless한 핸드오프를 위해 RN간에 멀티캐스트 그룹 메커니즘을 이용할 경우, 핸드오프 예상시간에 따라 등급별로 버퍼를 다르게 할당하여 멀티캐스트 하는 방법과 단순 멀티캐스트 하는 방법이 있다. 본 논문은 Micro Mobility를 지원하기 위한 멀티캐스트 그룹 메커니즘 기반의 Seamless 핸드오프 알고리즘에서 등급별로 버퍼를 다르게 할당할 경우와 단순 멀티캐스트 할 경우의 블록킹 확률을 비교 분석한다.