• KIPS Transactions on Computer and Communication Systems
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• v.11 no.1
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• pp.9-22
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• 2022

Virtual Reality(VR) technology is an interface technology that is actively used in various audio-visual-based applications by showing users a virtual world composed of computer graphics. Since VR-based applications are graphic processing-based applications, expensive computing devices equipped with Graphics Processing Unit(GPU) are essential for graphic processing. This incurs a cost burden on VR application users for maintaining and managing computing devices, and as one of the solutions to this, a method of operating services in cloud environments is being used. This paper proposes a performance management technique to address the problem of performance interference between containers owing to GPU resource competition in container-based high-performance cloud environments in which multiple containers share a single GPU. The proposed technique reduces performance deviation due to performance interference, helping provide uniform performance-based remote VR services for users. In addition, this paper verifies the efficiency of the proposed technique through experiments.

• Journal of Industrial Convergence
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• v.20 no.1
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• pp.63-68
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• 2022

In schools and corporate buildings, public WiFi Access Points are installed on the ceilings of hallways. In the case of an architectural structure in which a WiFi signal enters through a steel door made of a material with high signal attenuation, Internet connection is frequently cut off or fails when the door is closed. To solve this problem, our research implements an economical and portable WiFi extender using a Raspberry Pi and an auxiliary battery. Commercially available WiFi extenders have limitations in the location where the power plug is located, and WiFi extension using the WiFi hotspot function of an Android smartphone is possible only in some high-end models. However, because the proposed device can be installed at the position where the Wi-Fi reception signal is the best inside the door, the WiFi range can be extended while minimizing the possibility of damage to the original signal. Experimental results show that it is possible to eliminate the shadows of radio waves and to provide Internet services in the office when the door is closed, to the extent that web browsing and real-time video streaming for 720p are possible.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.10
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• pp.333-344
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• 2022

In a container-based cloud environment, multiple containers can share a graphical processing unit (GPU), and GPU sharing can minimize idle time of GPU resources and improve resource utilization. However, in a cloud environment, GPUs, unlike CPU or memory, cannot logically multiplex computing resources to provide users with some of the resources in an isolated form. In addition, containers occupy GPU resources only when performing GPU operations, and resource usage is also unknown because the timing or size of each container's GPU operations is not known in advance. Containers unrestricted use of GPU resources at any given point in time makes managing resource contention very difficult owing to where multiple containers run GPU tasks simultaneously, and GPU tasks are handled in black box form inside the GPU. In this paper, we propose a container management technique to prevent performance degradation caused by resource competition when multiple containers execute GPU tasks simultaneously. Also, this paper demonstrates the efficiency of container management techniques that analyze and propose the problem of degradation due to resource competition when multiple containers execute GPU tasks simultaneously through experiments.

• KIPS Transactions on Computer and Communication Systems
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• v.10 no.5
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• pp.123-136
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• 2021

RPC (Remote Procedure Call)-based Graphics Processing Unit (GPU) virtualization technology is one of the technologies for sharing GPUs with multiple user virtual machines. However, in a cloud environment, unlike CPU or memory, general GPUs do not provide a resource isolation technology that can limit the resource usage of virtual machines. In particular, in an RPC-based virtualization environment, since GPU tasks executed in each virtual machine are performed in the form of multi-process, the lack of resource isolation technology causes performance degradation due to resource competition. In addition, the GPU memory competition accelerates the performance degradation as the resource demand of the virtual machines increases, and the fairness decreases because it cannot guarantee equal performance between virtual machines. This paper, in the RPC-based GPU virtualization environment, analyzes the performance degradation problem caused by resource contention when the GPU memory requirement of virtual machines exceeds the available GPU memory capacity and proposes a GPU memory management technique to solve this problem. Also, experiments show that the GPU memory management technique proposed in this paper can improve the performance of GPGPU tasks.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.6
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• pp.69-75
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• 2022

We propose energy-efficient scheduling considering real-time constraints and energy efficiency in smart mobile with heterogeneous multi-core structure. Recently, high-performance applications such as VR, AR, and 3D game require real-time and high-level processings. The big.LITTLE architecture is applied to smart mobiles devices for high performance and high energy efficiency. However, there is a problem that the energy saving effect is reduced because LITTLE cores are not properly utilized. This paper proposes a heterogeneous multi-core assignment technique that improves real-time performance and high energy efficiency with big.LITTLE architecture. Our proposed method optimizes the energy consumption and the execution time by predicting the actual task execution time using SVM (Support Vector Machine). Experiments on an off-the-shelf smartphone show that the proposed method reduces energy consumption while ensuring the similar execution time to legacy schemes.

• The Korean Journal of Applied Statistics
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• v.36 no.4
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• pp.337-347
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• 2023

Sampling designs often use stratified sampling, where elements or clusters of the study population are divided into strata and an independent sample is chosen from each stratum. The stratification strategy consists of stratification and sample allocation, which are important issues that are repeatedly considered in survey sampling. Although a stratified multistage sample design is often used in practice, the literature tends to discuss simple sampling in terms of stratum effects or stratum efficiency. This study examines an existing stratum efficiency measure for two-stage sampling and further proposes additional stratum efficiency measures using the design effect model. The proposed measures are used to evaluate the stratification strategy of the sample design for high school students of the 4^th Korean National Environmental Health Survey (KoNEHS).

• Journal of Software Assessment and Valuation
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• v.15 no.1
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• pp.97-102
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• 2019

In this paper, we propose a method to remotely intuitively identify faults found in storage devices in soft-RAID used in a server system composed of Linux. To do this, we analyze the principle and problem of fault reporting method in the soft-RAID system of Linux OS and suggest the state of storage devices in remote Internet Home-page. The proposed method consists of a method of displaying images on the Internet home-page, so that it can be arranged freely when creating a home-page, and the image data is composed of external files, so it is bery convenient to edit and replace images In order to verify the effectiveness of the proposed method, we have confirmed that the state of each storage device can be confirmed at a long distance without any major addition to the Home-page configuration.

• Convergence Security Journal
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• v.23 no.5
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• pp.151-156
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• 2023

Currently, ICT is widely used in caring for the elderly living alone and preventing the disappearance of the elderly with dementia. Therefore, in this study, based on the government policy direction for the 4th industrial revolution, the use of AI technology-based care services, which are gradually increasing in community care, was sought to explore the current status and prospects for utilization and activation.AI speakers and caring robots, services that can be used for community care, help solve various problems experienced by the elderly, and are also used to relieve lack of conversation or loneliness by adding emotional functions. In order to activate community care using AI technology in the future: First, there is a need for continuous education to familiarize the elderly with AI devices and 'user experience (UX) design' for the elderly. Second, it is necessary to use human-centered technology that has a complementary relationship and enables emotional mutual relationships rather than using function-oriented technology. Third, it is necessary to solve ethical problems such as guaranteeing the user's right to self-determination and protecting privacy.

• Convergence Security Journal
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• v.23 no.4
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• pp.93-100
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• 2023

This paper presents a novel approach for assigning group keys within a dynamic swarm unmanned system environment. In this environment, multiple groups of unmanned systems have the flexibility to merge into a single group or a single unmanned system group can be subdivided into multiple groups. The proposed protocol encompasses two key steps: group key generation and sharing. The responsibility of generating the group key rests solely with the leader node of the group. The group's leader node employs a secret sharing scheme to fragment the group key into multiple fragments, which are subsequently transmitted. Nodes that receive these fragments reconstruct a fresh group key by combining their self-generated secret fragment with the fragment obtained from the leader node. Subsequently, they validate the integrity of the derived group key by employing the hash function. The efficacy of the proposed technique is ascertained through an exhaustive assessment of its security and communication efficiency. This analysis affirms its potential for robust application in forthcoming swarm unmanned system operations scenarios characterized by frequent network group modifications.

• 한국HCI학회:학술대회논문집
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• 2006.02c
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• pp.854-858
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• 2006

디지털화의 가속, 고속 통신 인프라의 확대 등으로 전자, 정보 통신 기기들이 단일 네트워크로 연결되어 영상 및 음향 정보를 서로 공유할 수 있으며, 생활 공간 내에서 실생활의 질 향상을 위한 지능적 정보 서비스와 자연스럽고 편한 내추럴 인터페이스 기술에 의한 지능형 반응 정보 서비스 공간 기술이 중요한 이슈로 등장하고 있다. 본 연구에서는 지능형 반응 공간의 물리적 객체로서 학교, 연구 기관 및 회사 등의 회의실을 선정한다. 그리고, 이를 대상으로 회의 참여자들이 자연스럽고 편리하게 의견 교환, 관련 자료 및 정보 처리를 할 수 있는 시스템 구축을 위한 아키텍처에 대하여 논의한다. 본 연구에서 제안하는 시스템 아키텍처는 회의와 관련된 문서나 회의 내용 등의 정보를 실감 가시화 노드로 추상화되고 메타 정보화함으로써 전체 회의 내용의 파악과 회의 정보에 대한 체계적이고 논리적인 관리를 가능하게 한다. 또한 여러 사람의 공동 작업을 필요로 하는 정보 또는 문서에 대한 동시 편집 기능과 자연스러운 동작에 의한 데이터 조작을 지원하는 실감 워크벤치 및 워크스크린 기술, 정보 핸들링의 다양성과 조작의 편리성을 위한 실감 아이콘에 의하여 자연스럽고 편리한 회의를 가능하게 한다. 그리고, 이러한 요소 기술들이 에이전트에 의해 회의 프로세스 및 요소 기술들의 시스템적 통합을 가능하게 한다.