• Journal of Broadcast Engineering
• /
• v.12 no.3
• /
• pp.278-288
• /
• 2007

We propose the fast full search algorithm that reduces the computational load of the block matching algorithm which is used for a motion estimation in the video coding. Since the conventional spiral search method starts searching at the center of the search window and then moves search point to estimate the motion vector pixel by pixel, it is good for the slow motion picture. However we proposed the efficient motion estimation method which is good for the fast and slow motion picture. Firstly, when finding the initial threshold value, we use the expanded predictor that can approximately calculate minimum threshold value. The proposed algorithm estimates the motion in the new search order after partitioning the search window and adapt the directional search order in the re-divided search window. At the result, we can check that the proposed algorithm reduces the computational load 94% in average compared to the conventional spiral full search algorithm without any loss of image quality.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.6
• /
• pp.627-634
• /
• 2016

Vehicle classification system in domestic tollgates is usually to use treadle sensor for calculating wheel width and tread of the vehicle. due to the impact that occurs when the wheels of the vehicle contact, treadle sensor requires high durability. recently, KHC(Korea Highway Corporation) began operating high-speed lane for cargo truck. high-speed cargo truck generate more impact the design criteria of previous treadle. therefore, an increase in the maintenance and management costs of the treadle damage is concerned. In this paper, we propose an algorithm for obtaining optimal wheel width and tread using non-contact treadle sensor that been improved durability from physical impacts. for the verification of the proposed algorithm, a field test was performed using 1/2/3/6 class vehicles based on the KHC's classification criteria. through this experiments, maximum error of the width and the tread is each ${\pm}2cm$ and ${\pm}8cm$, also the accuracy was measured as 98%, 97% or more, and proved that the proposed algorithm valid on to apply to the vehicle classification system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.1C
• /
• pp.9-15
• /
• 2007

We propose the fast full search algorithm that reduces the computation of the block matching algorithm which is used for motion estimation of the video coding. Since the conventional spiral search method starts searching at the center of the search window and then moves search point to estimate the motion vector pixel by pixel, it is good for the slow motion pictures. However the proposed method is good for the fast and slow motion because it estimates the motion in the new search order after partitioning the search window. Also, when finding the motion vector, this paper presents the method that reduces the complexity by computing the matching error in the order which is determined by local image complexity. The proposed algorithm reduces the computation up to 99% for block matching error compared with the conventional spiral full search algorithm without any loss of image quality.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.20-20
• /
• 2010

반도체 공정 등에서 10-6~10-8 Torr의 고진공 환경을 제공하기 위하여 사용되는 고진공 터보분자펌프 (Turbomolecular Pump, TMP)는 다층의 회전깃을 갖는 로터를 회전시켜 분자를 배출시키는 방식을 사용하는 진공펌프이다. 또한 최근에는 디스플레이 및 반도체 공정에서 높은 진공도뿐만 아니라, 높은 배기속도를 요구하는 추세에 따라, 터보 펌프와 드래그 펌프부분을 동시에 가지고 있어 상대적으로 작동 진공도 영역이 넓은 복합 분자펌프(Compound Turbomolecular Pump, CMP)의 활용도가 넓어지고 있다. 이러한 분자펌프가 장시간의 고속회전에 적합하도록 비접촉 방식인 자기부상 방식의 적용이 최근 거의 표준화되어 있다. 자기베어링 시스템은 전자기력을 이용하여 자성체인 회전축을 부상지지 함으로써 비접촉 고속 회전이 가능하여 윤활이 용이하지 않은 진공 환경 등 가혹한 환경에 적합하며, 터보분자펌프는 자기베어링이 가장 널리 사용되고 있는 분야이기도 하다. 자기베어링 시스템의 설계는 크게 하드웨어와 소프트웨어로 나누어질 수 있는데, 하드웨어의 경우 전체 로터 시스템의 특성을 고려하여 설계되어야 하며, 주로 자기베어링 코어와 코일, 변위센서 및 전력 증폭 시스템 등의 기전적인 요소들이 이루어져 있다. 하드웨어 설계와 함께 제어시스템의 설계도 매우 중요하며, 이는 자기베어링 시스템이 불안정한 특성을 갖는 개루프계를 갖고 있으므로 안정화를 위한 능동제어 시스템이 필수적이며 진동제어 등 여러 가지 기능이 요구되기 때문이다. 본 논문에서는 이러한 자기부상형 고진공 복합분자펌프의 제어를 위한 선형제어시스템의 구성을 실제 시스템의 적용을 통하여 설명하였다. 각 제어기는 DSP 를 이용한 디지털 제어시스템으로 구성되었으며, 2, 500 l/s 급의 복합 분자펌프 시작품에 적용하여 10,000 rpm까지의 기본성능시험을 수행하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.8
• /
• pp.718-727
• /
• 2016

Korean ground systems have started to be developed for mission control and payload data processing since 1990s. International technology cooperations were needed in the early development phase of ground system for science experiment satellite, LEO satellite and GEO satellite and then they have been developed as domestic own technology since acquiring early technology. Our country has developed total 14 ground systems until now, this paper suggests prospect and direction on ground system development in the base of such development experiences. Mission control system is needed to develop multi-satellite mission control system in the base of technology of re-configure, re-use and automation. Processing system is needed to acquire processing technology for kinds of payload sensor data and study inter-operation to integrate and use outputs which are processed between users. Finally, national ground system infrastructure is needed to operate kinds of lots of satellites at worldwide area.

• KIISE Transactions on Computing Practices
• /
• v.22 no.9
• /
• pp.405-418
• /
• 2016

Recently, many researchers have studied the VSL decision method using traffic information in multiple detector zones. However, this method selects incorrect VSL starting points, leading to the selection of the wrong speed control zone and calculation of the wrong VSL, causing traffic congestion. Eventually, the Unstable VSL system causes more congestion on the freeway. This paper proposes an improved VSL algorithm stably operated in multiple detector zones on the Korea highway. The proposed algorithm selects a preliminary VSL start station (VSS) expected to end the congestion using the acceleration of stations. It also determines the VSS at each congestion area. Finally, it calculates the VSL relative to the determined VSS and controls the vehicles that enters the traffic congestion zone. The developed strategy is compared with Real-time Variable Speed Limits for Urban Freeway (RVSL) to test the stability and efficiency of the proposed algorithm. The results show that the proposed algorithm resolves the problems of the existing algorithm, demonstrated by the correct VSS decision and the reduction of total travel time by 1-2 minutes.

• Journal of Welding and Joining
• /
• v.26 no.2
• /
• pp.92-97
• /
• 2008

In welding of thin plate, some defects such as melt through and unmelted zone occur easily at welding start, however there is a limited study on those problems. Therefore the effects of start block and arc length on melt through and unmelted zone at start were investigated in this study. When start block height was lower than base metal, there was melt through at start. And when the height was even with base metal, no unmelted zone existed. Unmelted zone was increased as start block height increased from 0mm to 0.5mm. However unmelted zone was not much changed as the height increasing from 0.5mm to 1.0mm. When gap existed between start block and base metal, melt through occurred. However, unmelted zone was increased as the contact force of start block on base metal was increased from 0kgf to 7.5kgf. And when arc length was decreased from 3.8mm to 3.0mm, unmelted zone was decreased. It was concluded that the optimum condition to prevent melt through and to minimize unmelted zone would be with start block height 0.25mm, contact force 3.0kgf, and arc length 3.4mm. This optimum condition was applied to the mass production line and resulted in satisfied outcome.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.2A
• /
• pp.20-25
• /
• 2005

A high performance Viterbi decoder is designed using modified register exchange scheme and block decoding method. The elimination of the trace-back operation reduces the operation cycles to determine the merging state and the amount of memory. The Viterbi decoder has low latency, efficient memory organization, and low hardware complexity compared with other Viterbi decoding methods in block decoding architectures. The elimination of trace-back also reduces the power consumption for finding the merging state and the access to the memory. The proposed decoder can be designed with emphasis on either efficient memory or low latency. Also, it has a scalable structure so that the complexity of the hardware and the throughput are adjusted by changing a few design parameters before synthesis.

• The Journal of Korean Institute of Information Technology
• /
• v.17 no.6
• /
• pp.9-16
• /
• 2019

Companies that want to improve their manufacturing processes have recently introduced the smart factory, which is particularly noticeable. The ultimate goal is to maximize the area of the smart factory that performs the process of the production facility completely with minimal manual control and to minimize errors of reasoning. This research is a part of a project for unmanned production, management, packaging, and delivery management and the detection of the start point of rebars to perform the automatic calibration of the rollers through the tracking of the automated facilities of unmanned production. It must meet the requirement to accurately track the position from the start point to the end point. In order to improve the tracking performance, it is important to set the accurate start point. However, the probability of tracking errors is high depending on environments such as illumination and dust through the conventional time-based detection method. In this paper, we propose a starting point detection method using the average brightness change of high speed IR camera to reduce the errors according to the environments, As a result, its performance is improved by more than 15%.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.4C
• /
• pp.331-340
• /
• 2006

In this Paper, we propose to extend the TSS-LS(Two-Step Search scheme with Linear search based Second step) scheme which was already proposed by the authors for coherent UWB(Ultra Wide Band) systems, to rapid and reliable acquisition of noncoherent UWB systems in multipath channels. The proposed noncoherent TSS-LS employing simple energy window banks utilizes two different thresholds and search windows to achieve fast acquisition. Furthermore, the linear search is adopted for the second step in the proposed scheme to correctly find the starting point in the range of effective delay spread of the multipath channels, and to obtain reliable BER(Bit Error Rate) performance of the noncoherent UWB systems. Simulation results with multipath channel models by IEEE 802.15.3a show that the proposed two-step search scheme can achieve significant reduction of the required mean acquisition time as compared to general search schemes. ]n addition, the proposed scheme achieves quite good BER performance for large signal-to-noise ratios, which is favorably comparable to the case of ideal perfect timing.