• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.4856-4871
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• 2015

Backpressure based scheduling has been considered as a promising technique for improving the throughput of a wide range of communication networks. However, this scheduling technique has not been well studied for heterogeneous wireless networks. In this paper, we propose a virtual-queue based backpressure scheduling (VQB) algorithm for heterogeneous multi-hop wireless networks. The VQB algorithm introduces a simple virtual queue for each flow at a node for backpressure scheduling, whose length depends on the cache size of the node. When calculating flow weights and making scheduling decisions, the length of a virtual queue is used instead of the length of a real queue. We theoretically prove that VQB is throughput-optimal. Simulation results show that the VQB algorithm significantly outperforms a classical backpressure scheduling algorithm in heterogeneous multi-hop wireless networks in terms of the packet delivery ratio, packet delivery time, and average sum of the queue lengths of all nodes per timeslot.

• Journal of Information Processing Systems
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• v.12 no.4
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• pp.612-630
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• 2016

As mobile augmented reality technologies are spreading these days, many users want to produce augmented reality (AR) contents what they need by themselves. To keep pace with such needs, we have developed a mobile AR contents builder (hereafter referred to as MARB) that enables the user to easily connect a natural marker and a virtual object with various interaction events that are used to manipulate the virtual object in a mobile environment so that users can simply produce an AR content using natural photos and virtual objects that they select. MARB consists of five major modules-target manger, virtual object manager, AR accessory manager, AR content manager, and AR viewer. The target manager, virtual object manager and AR accessory manager register and manage natural target markers, various virtual objects and content accessories (such as various decorating images), respectively. The AR content manger defines a connection between a target and a virtual object with enabling various interactions for the desired functions such as translation/rotation/scaling of the virtual object, playing of a music, etc. AR viewer augments various virtual objects (such as 2D images, 3D models and video clips) on the pertinent target. MARB has been developed in a mobile application (app) format in order to create AR contents simply using mobile smart devices without switching to a PC environment for authoring the content. In this paper, we present the detail organizations and applications of MARB. It is expected that MARB will enable ordinary users to produce diverse mobile AR contents for various purposes with ease and contribute to expanding the mobile AR market based on spread of a variety of AR contents.

• Journal of The Korean Association For Science Education
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• v.42 no.2
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• pp.177-184
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• 2022

This article aims to explain the concept and characteristics of the 'Intelligent Science Lab', which is being promoted nationwide in Korea since 2021. The Korean Ministry of Education creates a master plan containing a vision for science education every five years. The most recently announced '4th Master plan for science education (2020-2024)' emphasizes the policy of setting up an 'intelligent science lab' in all elementary and secondary schools as an online and offline space for scientific inquiry using advanced technologies, such as Internet of Things and Augmented and Virtual Reality. The 'Intelligent Science Lab' project is being pursued in two main directions: (1) developing an online platform named 'Intelligent Science Lab-ON' that supports science inquiry classes, and (2) building a science lab space in schools that encourages active student participation while utilizing the online platform. This article presents the key features of the 'Intelligent Science Lab-ON' and the characteristics of intelligent science lab spaces newly built in schools. Furthermore, it introduces inquiry-based science learning programs developed for intelligent science labs. These programs include scientific inquiry activities in which students generate and collect data ('data generation' type), utilize datasets provided by the online platform ('data utilization' type), or utilize open and public data sources ('open data source' type). The Intelligent Science Lab project is expected to not only encourage students to engage in scientific inquiry that solves individual and social problems based on real data, but also contribute to presenting a model of online and offline linked scientific inquiry lessons required in the post-COVID-19 era.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.448-455
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• 2014

Virtual Fire Control System(VFCS) in attack helicopter is developed. VFCS is comprised of multifunction display, store management computer, mission computer, target acquisition and designation system, mission planning system, weapon simulator and flight simulator. Weapon engagement process under the operational environment of helicopter was considered by using the VFCS. We considered hellfire missile, tow missile, unguided rocket and turret gun. The results of this study will be utilized efficiently on integrated fire control system SIL(System Integration Lab.) in attack helicopter.

• Journal of Korean Academy of Addiction Psychiatry
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• v.18 no.1
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• pp.17-22
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• 2014

Virtual reality (VR) provides an immersive and interactive 3-dimensional system, which allows an individual to become immersed in a computer-generated situation. VR technology has been administered in the exposure-based treatment of a variety of psychiatric disorders, including acrophobia, fear of flight, and post-traumatic stress disorder. Furthermore, VR systems have also been developed for the use of research and treatment in addiction. They might have advantages in cue exposure therapy, by increasing the salience of cues, as well as assessments of cue reactivity in addiction. This article summarizes the application of VR in the field of psychiatry. More importantly, it suggests the possibilities of clinical use of VR technology, in the treatment of addiction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.762-763
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• 2002

Recently, automatic control or application of measuring instrument with computers is rapidly increasing. In this paper we designed automatic incubation system that has functions of control and monitoring of measuring instrument, analysis of measured data, and automatic control by using LabVIEW graphic program that can easily collect, control, analyze, and apply data. Then to inspect the system we produced Incubator. Internal environment is measured by a sensor and each device is setting and controlled to create the optimum environment after finding hatching environment of selected individual from Database file for incubation. Through this functions, problems of hatching rate and quality that were affected by minute change of hatching environment are dealt successfully with, and retrenchment of labor and cost is expected as well.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.47-48
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• 2006

본 논문에서는 LabVIEW를 이용한 휴대용 3상 유도전동기 회전자 바 고장 진단 시스템을 개발하였다. LabVIEW는 NI사에서 개발한 그래픽컬 프로그래밍 언어로서 VI(Virtual Instrument)기술을 이용하여 계측, 분석, 표현 프로그램에 최적화된 언어이다. 유도전동기의 입력단에 Current Probe를 연결하여 전류를 측정하였고, NI사의 USB-DAQ보드를 이용하여 데이터를 수집한 후 노트북 컴퓨터에서 실행되는 LabVIEW 프로그램에 의해 고장을 진단할 수 있는 실시간 휴대용 진단 시스템을 개발하였다. 회전자 바에 고장이 일어나면 선 전류의 불균형, 손실 증가, 토크맥동과 평균 토크의 감소를 가져올 수 있다. 고장 진단 방법으로는 회전자 바 고장의 특징 주파수를 찾아 진단하는 방법이 있다. 회전자 바 고장에 대하여 1개와 2개 바를 절단한 회전자를 사용하여 각각 실험하였으며, FFT 분석에 의하여 실시간으로 유도전동기 회전자 바 고장을 진단 할 수 있음을 보였다.

• Proceedings of the CALSEC Conference
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• 1998.10b
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• pp.375-389
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• 1998

o Projects/Subprojects/Tasks Distributed over Teams, Departments, Enterprises and the Globe o Virtual Teaming/Enterprises o Limitations/Barriers on Distributed Work - Geographical - Communication(omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.281-282
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• 2013

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.88-93
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• 2006

대부분의 입체 영상물은 단지 화면을 입체로 보여주는 것만이 목적이다. 그러나 만약 입체 영상으로 표현된 가상 물체를 손가락을 뻗어 실제로 만져볼 수 있다면 현실감은 더욱 증가할 것이다. 본 연구에서는 입체영상 장치로 만든 가상 비누방울들을 실제 자기 손가락으로 터뜨리는 듯한 느낌을 가질 수 있도록 해주는 가상 현실 게임 시스템을 만들었다. 이 때 두 개의 위치/방향 센서를 이용하여 손가락 끝과 머리의 움직임을 추적하여 가상 공간과 현실 공간의 두 좌표계를 서로 일치시켜 볼 수 있도록 하였으며, 자체 제작한 진동촉각 장치를 이용하여 비누방울을 터뜨릴 때 손가락에 약한 진동 촉감을 제공하여 실제로 자신이 비누방울을 터뜨리는 듯한 느낌을 갖도록 하였다. 이러한 시도를 통해 입체영상 기술을 이용한 가상현실 게임에서의 진동촉각 장치의 활용 가능성을 확인하였다.