• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.201-209
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• 2003

Virtual human models are widely used to save time and expense in vehicle safety studies. A human model is an essential tool to visualize and simulate a vehicle driver in virtual environments. This research is focused on creation and application of a human model fer virtual reality. The Korean anthropometric data published are selected to determine basic human model dimensions. These data are applied to GEBOD, a human body data generation program, which computes the body segment geometry, mass properties, joints locations and mechanical properties. The human model was constituted using MADYMO based on data from GEBOD. Frontal crash and bump passing test were simulated and the driver's motion data calculated were transmitted into the virtual environment. The human model was organized into scene graphs and its motion was visualized by virtual reality techniques including OpenGL Performer. The human model can be controlled by an arm master to test driver's behavior in the virtual environment.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.3-9
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• 2015

We investigate rate scheduling and power allocation problem for a delay constrained CDMA systems. Specifically, we determine an energy efficient scheduling policy, while each user maintains the short term (n time slots) average throughput. We consider a multirate CDMA system where multirate is achieved by multiple codes. Each code can be interpreted as a virtual user. The aim is to schedule the virtual users into each time slot, such that the sum of transmit energy in n time slots is minimized. We then show that the total energy minimization problem can be solved by a shortest path algorithm. We compare the performance of the optimum scheduling with that of TDMA-type scheduling.

• Journal of the Korea Computer Graphics Society
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• v.6 no.4
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• pp.1-7
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• 2000

Traditionally, three dimension model s have been used for building virtual worlds, and a data structure called the "scene graph" is often employed to organize these 3D objects in the virtual space. On the other hand, image-based rendering has recently been suggested as a probable alternative VR platform for its photo-realism, however, due to limited interactivity. it has only been used for simple navigation systems. To combine the merits of these two approaches to object/scene representations, this paper proposes for a scene graph structure in which both 3D models and various image-based scenes/objects can be defined. traversed, and rendered together. In fact, as suggested by Shade et al. [1]. these different representations can be used as different LOD's for a given object. For in stance, an object might be rendered using a 3D model at close range, a billboard at an intermediate range. and as part of an environment map at far range. The ultimate objective of this mixed platform is to breath more interactivity into the image based rendered VE's by employing 3D models as well. There are several technical challenges in devising such a platform : designing scene graph nodes for various types of image based techniques, establishing criteria for LOD/representation selection. handling their transition s. implementing appropriate interaction schemes. and correctly rendering the overall scene. Currently, we have extended the scene graph structure of the Sense8's WorldToolKit. to accommodate new node types for environment maps. billboards, moving textures and sprites, "Tour-into-the-Picture" structure, and view interpolated objects. As for choosing the right LOD level, the usual viewing distance and image space criteria are used, however, the switching between the image and 3D model occurs at a distance from the user where the user starts to perceive the object's internal depth. Also. during interaction, regardless of the viewing distance. a 3D representation would be used, if it exists. Finally. we carried out experiments to verify the theoretical derivation of the switching rule and obtained positive results.

• Therapeutic Science for Rehabilitation
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• v.7 no.2
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• pp.17-27
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• 2018

Objective : The purpose of this study was to investigate the effect of occupational therapy intervention using a fully immersive virtual reality device on the upper extremity function of patients with chronic stroke. Methods : This study used a single subject (ABA) design. The study subjects was a chronic stroke patient with left lateral deviation. Four baseline periods, 12 intervention periods, and 4 baseline regression periods were performed for a total of 20 sessions for 10 weeks. OT intervention with a fully immersive virtual reality device was used every 30 minutes. BBT and WMFT evaluations were performed at each session and the results were displayed in a line graph. Results : The patient's upper limb function has improved. During baseline recurrence, efficacy of treatment was confirmed after removal of intervention, but no significant changes were observed. Conclusion : It has been found that OT intervention with a fully immersive virtual reality device for upper limb function in chronic stroke patients is an effective intervention. However, the effectiveness of maintaining treatment is not important, so we need to develop an easy-to-use home intervention program.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.4
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• pp.10-21
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• 2001

This paper develops a logical simulation method for by dyversity of situations. Most existing systems, for example, games and infant tutoring systems lead users to virtual environment with unfolding situations, but are not designed to induce the change of the environment itself. In this paper, a logically simulated environment is created by defining situations and single events based on situation hierarchy structure. We elaborate the occurrence of events by classifying the causality. The occurrence or natural phenomena is dictated by physical laws and natural phenomena are expressed as the transition of the event based on event association. Specifically we define the source of the event for natural phenomena and we consider the existence of objects as a primary factor in event occurrence. The advantages of this approach include the reuse of events, that is, different events can be generated in the same flow with fresh conditions. This allows us to implement a more practical and logical environment. A drawback to this method is the difficulty in dividing a situation into events. The proposed method was implemented in the context of the change of season among natural phenomena.

• The Transactions of the Korea Information Processing Society
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• v.5 no.7
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• pp.1896-1907
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• 1998

확장된 마크흐름선도(EMFG: Extednded Mark Flow Graph)는 기존의 MFG를 개선한 그래프로서, 회로변수식에 의해 실제회로로 쉽게 구현가능하므로 이산제어시스템의 모델링과 설계 및 구현의 강력한 도구로 사용될 수 있다. 본 논문은 EMFG의 트랜지션들이 점화하는 과정 및 트랜지션들이 점화완료하였을 때 각 박스들의 마크수 변화를 부울함수식과 벡터를 사용하여 표현하였다. 또한 시스템의 상태변화를 쉽게 판단할 수 있게 하는 EMFG의 동작알고리듬을 제안하였으며, 제안된 알고리듬은 3-비트 증가계수기를 설계한 EMFG와 시간트랜지션이 포함된 가상의 EMFG에서 잘 수행되었다. EMFG의 동작이 부울함수로 해석가능해짐으로 인해 시스템의 분석 및 설계가 용이하며 컴퓨터를 이용한 자동화된 시스템의 분석과 설계가 가능하다.

• The Journal of Society for e-Business Studies
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• v.8 no.4
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• pp.151-166
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• 2003

The Topic Maps paradigm allows people and organizations to integrate and merge heterogeneous products classification systems such as UNSPSC and HS. Merging their product ontologies could combine information about classification scheme for products. We analyzed two product classification schemes for UML modeling and developed an integrated TM for watches . Examples in XTM syntax show how UNSPSC and HS can be integrated by merging their ontology.

• Journal of the Korea Computer Graphics Society
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• v.9 no.2
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• pp.19-26
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• 2003

본 논문은 두개의 날개를 가진 다양한 생명체들의 형상과 움직임을 복잡한 공기역학 없이 body-brain 공진화를 사용하여 생성하는 시스템을 기술한다. 인공생명 기술이 다양한 가상생명체들을 생성하는데 이용되었지만 제한된 기하학적 요소들을 사용한 날개 생성의 어려움과 매우 복잡한 공기역학으로 인하여 하늘의 생명체들을 탐색한 연구들은 매우 드물다. 본 논문의 진화된 생명체들은 시스템의 단순함에도 불구하고 심미적인 모습과 유기적인 날개침 동작을 보여준다. 진화 알고리즘을 위한 유전형 인코딩에 쓰인 자료구조는 제한된 리스트 구조로서 이는 방향그래프와 유사하나 더욱 쉽게 다루어질 수 있다. 본 시스템으로 진화된 생명체는 연속적인 삼각형 패치로 이루어진 두개의 대칭형 날개를 가지며, 새, 나비, 박쥐 혹은 상상적인 용이나 익룡 등을 연상시키는 다양한 모습과 기동을 보여준다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.907-909
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• 2005

copy, load, store와 같은 데이터 이동 명령은 프로그램의 수행시간을 늘리며 코드의 크기도 증가시킨다. 따라서, 최적화 컴파일러의 레지스터 할당 단계에서 이런 데이터 이동 명령들을 줄이는 것이 중요하다. 데이터 이동명령을 줄이기 위해서 그래프 컬러링 기반의 레지스터 할당 기법의 다양한 개선안이 나와있다. 여기서는 이 중에서 조기 분할 레지스터 융합 기법을 VLIW 시뮬레이터에서 구현하여 그 성능을 확인해본다. 조기 분할 레지스터 융합 기법은 융합된 가상 레지스터가 가장 적은 비용을 가지는 레지스터를 포함하고 있는 경우, 융합된 레지스터 자체를 스필하지 않고, 잠재적 스필 단계에서 분리하여 적은 비용의 레지스터만을 스필하도록 하는 것이다.

• Journal of the Korea Computer Graphics Society
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• v.21 no.2
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• pp.11-20
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• 2015

We present a new interactive technique for directing the motion sequences of an animated character by dragging its specific body part to a desired location in the three-dimensional virtual environment via a hand motion tracking device. The motion sequences of our character is synthesized by reordering subsequences of captured motion data based on a well-known graph representation. For each new input location, our system samples the space of possible future states by unrolling the graph into a spatial search tree, and retrieves one of the states at which the dragged body part of the character gets closer to the input location. We minimize the difference between each pair of successively retrieved states, so that the user is able to anticipate which states will be found by varying the input location, and resultantly, to quickly reach the desired states. The usefulness of our method is demonstrated through experiments with breakdance, boxing, and basketball motion data.