• International Journal of Highway Engineering
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• v.14 no.1
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• pp.73-83
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• 2012

Effective use of traffic marking can lead to driver's safer driving by speed management and visibility enhancement. One of the critical factors in designing traffic marking is how to incorporate human factor issues into the design process. This study presented a methodology for evaluating the effectiveness of Hi-pass marking on Korean freeways based on kansei engineering. Hi-pass marking scenarios made by a virtual reality tool were used to evaluate the user's perceptions. Various combination of chevron angles and peripheral transverse(PT) bars were used for the evaluation. The results show that the most effective scenario is a combination of 60 degree chevron angle and an askew parallelogramshaped PT bar shaped. It is expected that the proposed method and outcome will be useful for making safer driving maneuvers.

• Journal of Platform Technology
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• v.6 no.2
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• pp.3-9
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• 2018

Recently VR environment is used in many areas including mobile learning, smart factory. However HMD(head-mounted display) is required to a dedicated and expensive system with high-end specification. When designing a VR system, it is needed to handle performance, mobility and usability. Many VR applications need to handle diverse sensors and user inputs continuously in a streaming manner. In this paper we design a VR mobile platform and implement a low-cost mobile VR HMD running on the platform. The VR HMD supports 3D contents delivery in a mobile manner. It is used to detect the motion detection based on angle value of a VR player from accelerator and gyro sensor. The MPU-6050, 6-axis sensor, is used to get a sensory value and the sensory value is taken as an input to a VR rendering server on a Unity game engine that is generated 3D images.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.347-350
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• 2004

A space radiation analysis has been used to evaluate an ability of electronic equipment boxes or spacecrafts to endure various radiation effects, so it helps design thicknesses of structure and allocate components to meet the radiation requirements. A comparison study of space radiation dose analysis programs SPENVIS Sectoring Tool (SST) and SIGMA II is conducted through some structure cases, simple sphere shell, box and representative satellite configurations. The results and a discussion of comparison will be given. A general comparison will be shown for understanding those programs. The both programs use the same strategy, solid angle sectoring with ray-tracing method to produce an approximate dose at points in representative simple and complex models of spacecraft structures. Also the particle environment data corresponding to mission specification and radiation transport data are used as input data. But there are distinctions between them. The specification of geometry model and its input scheme, the assignment of dose point and the numbers, the prerequisite programs and ways of representing results will be discussed. SST is a web-based interactive program for sectoring analysis of complex geometries. It may be useful for a preliminary dose assessment with user-friendly interfaces and a package approach. SIGMA II is able to obtain from RSICC (Radiation Safety Information Computational Center) as a FOR-TRAN 77 source code. It may be suitable for either parametric preliminary design or detailed final design, e.g. a manned flight or radiation-sensitive component configuration design. It needs some debugs, recompiling and a tedious work to make geometrical quadric surfaces for actual spacecraft configuration, and has poor documentation. It is recommend to vist RSICC homepage and GEANT4/SSAT homepage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1037-1047
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• 2001

In this paper, the capacity for the reverse link of the imperfect power controlled DS/CDMA hierarchical cellular system is analyzed considering imperfect sectorization in shadowing environment. Unlike the theoretical assumption, the power control of the DS/CDMA hierarchical cellular system is not perfect. Therefore, we consider various parameters such as the imperfect power control, the imperfect sectorization, the processing gain and the number of microcell interferers, which cause the capacity variation of the DS/CDMA hierarchical cellular system. It is shown that the capacity of DS/CDMA hierarchical cellular system is decreased according to the increase of the deviation of the imperfect power control, the overlapped angle, the power ratio between macrocell and microcell and to the decrease of processing gain, the number of microcell interfering users. Also, it is observed that the hierarchical cellular system can increase the user capacity from 1.54 to 3.89 times compared to the homogeneous macro-cellular system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1931-1940
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• 2014

In this paper, we propose a new hand shape recognition algorithm based on the geometric features using the convex-hull from the depth image acquired by Kinect system. Kinect is a camera providing a depth image and user's skeleton information and used for detecting hand region. In the proposed algorithm, hand region is detected in a depth image acquired by Kinect and convex-hull of the region is found. Boundary points caused by noise and unnecessary points for recognition are eliminated in the convex-hull that changes depending on hand shape. Hand shape is recognized by the sum of internal angle of a polygon that is matched with convex-hull reconstructed with selected boundary points. Through experiments, we confirm that proposed algorithm shows high recognition rate not only for five models but also those cases rotated.

• Journal of Korea Multimedia Society
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• v.14 no.4
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• pp.517-528
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• 2011

In this paper, we propose an indoor navigation system that can do walk safely to the destination for visually impaired persons. The proposed system analyzes images taken with the camera finds the ID of the marker to identify the absolute position of the pedestrian. Using the distance and angle obtained from IMU(Inertial Measurement Unit) accelerometer sensor and a gyro sensor, the system decides the relative position of a pedestrian for the previous position to determine the next direction. At the same time, we simplify a complex spatial structure in front of user by means of ultrasonic sensors and determine an avoidance direction by estimating the patterns. Then, it uses a few IR(Infrared Rays) sensors to detect stair. Our system offers position of visually impaired persons incorporating multiple sensors and helps users to arrive to destination safely.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.757-764
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• 2013

A panoramic video which supports to make viewers feel an immersion through fitting to a wide field of view (FOV) larger than the human visual angle needs an interactive viewing method such as selecting targeted view point among widely viewing points of a panoramic video because it difficult to simultaneously view a whole panoramic video due to a limited viewing environment and bandwidth. When a user officially uses a view navigation in order to select a view point, it happens waste of resources such as bandwidth owing to the transmitted video data of unnecessary view points. Therefore, this paper proposes the spatial-temporal prediction filter (STPF) which is based on the direction and velocity of the view navigation for transmitting only the necessary video data. As a result of simulation, STPF reduces bitrate saving rates by from 6% to 37% compared to conventional methods in the interactive panoramic video streaming service required high bandwidth.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.3
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• pp.271-274
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• 2006

This paper deals with a similarity decision method between the shape of hand-postures and their structures to improve performance of the vision-based hand-posture recognition system. Hand-posture recognition by vision sensors has difficulties since the human hand is an object with high degrees of freedom, and hence grabbed images present complex self-occlusion effects and, even for one hand-posture, various appearances according to viewing directions. Therefore many approaches limit the relative angle between cameras and hands or use multiple cameras. The former approach, however, restricts user's operation area. The latter requires additional considerations on the way of merging the results from each camera image to get the final recognition result. To recognize hand-postures, we use both of appearance and structural features and decide the similarity between the two types of features by learning.

• Journal of the Korea Society for Simulation
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• v.27 no.1
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• pp.33-38
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• 2018

This paper introduces the simulation concepts and technical approach of wire-guided torpedo performance analysis simulator, as a consequence, provide a framework for understanding overall attack procedures and effectiveness of tactics to torpedo operator. It described the mathematical models of simulation components and weapon engagement principle, especially it derived the closed-form solution of time consumption and leading angle problem of torpedo attack situation based on geographical assumption. In addition, it adopted the proportional navigation guidance at final stage of torpedo attack and also consider the tradeoff relation between target ship speed(propeller noise level) and detection probability, so that it improves the fidelity of physical realism. Simulator is developed with high degree of freedom in the perspective of tactical situation, and it helps user to understand the overall situation and tactical effectiveness.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.82-93
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• 2019

In this paper, the ductile fracture criteria for a marine structural steel (EH36) are presented and validated. The theoretical background of the recently developed Hosford-Coulomb (HC) fracture strain model and the DSSE fracture strain model which was developed to apply to the shell elements is described. In order to accurately estimate the flow stress in the large strain range up to the fracture, the material constants for the combined Swift-Voce constitutive equation were derived by the numerical analyses of the smooth and notched specimens made from the EH36 steel. As a result of applying the Swift-Voce flow stress to the other notched specimen model, a very accurate load - displacement curve could be derived. The material constants of the HC fracture strain and DSSE fracture strain models were independently calibrated based on the numerical analyses for the smooth and notch specimen tests. The user subroutine (VUMAT of Abaqus) was developed to verify the accuracy of the combined HC-DSSE fracture strain model. An asymmetric notch specimen was used as verification model. It was confirmed that the fracture of the asymmetric specimen can be accurately predicted when a very small solid elements are used together with the HC fracture strain model. On the other hand, the combined HC-DSSE fracture strain model can predict accurately the fracture of shell element model while the shell element size effect becomes less sensitive.