• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.717-720
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• 2004

Jini는 선 마이크로시스템즈에서 제안한 미들웨어 이다. Jini는 각종 디바이스나 소프트웨어들이 하나의 큰 시스템에 연결된 것처럼 서로 정보를 주고받고, 공유하고, 제어할 수 있는 동적인 분간 연합 시스템의 구축을 목표로 한다. Jini는 UPnP, HAVi와 함께 흠 네트워크의 주요 미들웨어로 꼽힌다. 홈 네트워크에서 프라이버시 보호, 방범, 둥의 보안은 아주 중요하며 이를 위하여 Jini에서도 시큐리티를 보강하여 2.0 버전을 2003년 11월에 발표하였다. 따라서 본 논문에서는 Jini 2.0의 시큐리티 분석 및 이를 홈 네트워크에서의 보안과 연관지어 기술하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권1호
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• pp.203-228
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• 2012

It is expected that device-to-device (D2D) communication is allowed to underlay future cellular networks such as IMT-Advanced for spectrum efficiency. This article studies the mechanisms of D2D communication and interference avoidance when the D2D subsystem reuses uplink resources and downlink spectrums with a cellular system, respectively. We firstly propose an effective scheme to establish and maintain D2D communication. Moreover, a novel method to deal with the resource allocation and interference avoidance issues by utilizing the network peculiarity of a hybrid network to share the uplink resource is proposed. Most research focuses on reusing the uplink spectrums, but how to share the downlink frequency bands is seldom addressed. To share the downlink spectrums and avoid the interference to the primary cellular devices, a labeled time slots based mechanism is proposed. Implementation details are described in a real cellular system and simulation results prove that satisfying performance can be achieved by using the proposed mechanisms.

• Journal of Information Technology Applications and Management
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• 제25권3호
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• pp.55-66
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• 2018

Early smart-work of company K was a technology-led way of applying ICT such as smart phones and mobile devices to business. After company K perceived the limitations of ICT-driven smart work, it propelled the work-smart, doing a work smart toward the way that human beings become central and a creative organizational culture is engendered. Company K propelled work-smart strategy in eight categories: simplification of data requirements, establishment efficient meeting culture, streamlining reporting and approval process, simplified document creation, overtime decrease, spreading flexible work system, settlement of healing leave, creating work-smart place. Company K set up an organizational culture secretariat dedicated to work-smart promotion and selected task priorities in consideration of urgency and effectiveness. Owing to such efforts, the company K's work-smart index rose sharply to 72 points this year from 56 points in the previous year. At the organizational culture survey, employees responded that organizational culture improved in all area. For a better future, company K analyzed its work-smart outcomes and planned progressively to improve its work-smart efforts based on employees opinions. This case study will serve as a guideline, for companies to make efforts to going forward to today work-smart beyond yesterday smart-work.

• 한국산업융합학회 논문집
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• 제23권6_2호
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• pp.999-1006
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• 2020

This study was conducted to develop an efficiency prediction program of a hydraulic secondary energy converter for calculating annual power generation of a Wavestar type wave power generator. Using the period and wave height obtained from the frequency domain analysis, the behavior of the floating body was obtained by assuming the sin function. The piston displacement and speed of the hydraulic cylinder were calculated considering the behavior of the floating body and the shape of the mechanism. The numerical simulation of the hydraulic system was performed by physically modeling the hydraulic cylinders, check valves, hydraulic motors, which are the main devices. In the future, this analysis program will be used to develop a program for estimating annual power generation of a moveable body type wave power generation device.

• International Journal of Computer Science & Network Security
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• 제21권3호
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• pp.212-218
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• 2021

Low-power and Lossy Networks (LLNs) have become the common network infrastructure for a wide scope of Internet of Things (IoT) applications. For efficient routing in LLNs, IETF provides a standard solution, namely the IPv6 Routing Protocol for LLNs (RPL). It enables effective interconnectivity with IP networks and flexibly can meet the different application requirements of IoT deployments. However, it still suffers from different open issues, particularly in large-scale setups. These include the node unreachability problem which leads to increasing routing losses at RPL sink nodes. It is a result of the event of memory overflow at LLNs devices due to their limited hardware capabilities. Although this can be alleviated by the establishment of multi-sink topologies, RPL still lacks the support for effective load balancing among multiple sinks. In this paper, we address the need for an efficient multi-sink load balancing solution to enhance the performance of PRL in large-scale scenarios and alleviate the node unreachability problem. We propose a new RPL objective function, Multi-Sink Load Balancing Objective Function (MSLBOF), and introduce the Memory Utilization metrics. MSLBOF enables each RPL node to perform optimal sink selection in a way that insure better memory utilization and effective load balancing. Evaluation results demonstrate the efficiency of MSLBOF in decreasing packet loss and enhancing network stability, compared to MRHOF in standard RPL.

• Journal of Multimedia Information System
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• 제9권1호
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• pp.51-60
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• 2022

This paper raised the need to examine how the online education environment triggered by COVID-19 and the smart learning environment can be established in consideration of the improvement of education and learning through learning analysis. Many studies are being conducted in Korea, and the Ministry of Education is continuously striving to build a smart school by promoting strategies for promoting smart education on the way to a talent powerhouse. Nevertheless, there is no unified definition of smart learning, and it can be seen as customized (individualized) learning using smart devices. However, most of the discussions on the construction of smart schools so far have limitations in that they are limited to physical spaces. Accordingly, the opinions of teachers and learners were not sufficiently reflected in the establishment of the facility. This study intends to study smart learning in various departments. In addition, the subjects students in charge of the co-researcher of this study were analyzed. The total number of subjects was 951, and 434 responded to this study survey. In addition, students were well accepting the online environment, and in the future, regardless of COVID-19, research will be presented to improve mutual communication between professors and students in smart learning.

• 한국산업융합학회 논문집
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• 제25권5호
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• pp.843-851
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• 2022

This paper was conducted to study the conditions for the manufacture and operation of artificial snow removal and ice-making test facilities so that the test equipment can be tested in a low-temperature environment using the polar environment performance test facility. The polar environment performance test Facility is designed to artificially simulate extreme environments up to -65 ℃, and is a mid-to-large low-temperature environment test facility that can perform performance tests on offshore plant equipment, ships, leisure, and offshore structures. To verify the safety of deck work of ships operating in polar environments, artificial snow removal and artificial ice making devices were manufactured, and we conducted research on various operating environments using these facilities. For the efficient operation of artificial snow and ice making facilities, it is important to continuously supply dry air, and it has been found that installing an additional heater at the tip of the nozzle is effective in preventing freezing.

• 한국정밀공학회지
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• 제11권5호
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• pp.33-41
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• 1994

For the establishment of large force standard and the accurate measurement of large force, 2MN hydraulic force standard machine which consists of loading frame, deadweight machine, two ram/cylinder systems and hydraulic control system was designed and fabricated. Measurement results of shapes for tow ram/cylinders reveal that the ratio of effective area is 200.094. The relative deviation of force stability for the machine is about .+-. 0.01% at 2MN and is less than .+-. 0.005% below 2MN. This machine may be widely used to calibrate the force measuring devices in industry and to test the force sensors.

• 한국전기전자재료학회논문지
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• 제37권4호
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• pp.347-357
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• 2024

Oxide semiconductor gas sensors are widely used for detecting toxic, explosive, and flammable gases due to their simple structure, cost-effectiveness, and potential integration into compact devices. However, their reliable gas detection is hindered by a longstanding issue known as humidity dependence, wherein the sensor resistance and gas response change significantly in the presence of moisture. This problem has persisted since the inception of oxide semiconductor gas sensors in the 1960s. This paper explores the root causes of humidity dependence in oxide semiconductor gas sensors and presents strategies to address this challenge. Mitigation strategies include functionalizing the gas-sensing material with noble metal/transition metal oxides and rare-earth/rare-earth oxides, as well as implementing a moisture barrier layer to prevent moisture diffusion into the gas-sensing film. Developing oxide semiconductor gas sensors immune to humidity dependence is expected to yield substantial socioeconomic benefits by enabling medical diagnosis, food quality assessment, environmental monitoring, and sensor network establishment.

• 상하수도학회지
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• 제37권6호
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• pp.447-456
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• 2023

Risk assessment on Jeju Special Self-Governing Province(JSSGP)'s water supply facilities and establishment of adaptation measures for climate crisis factors were implemented. JSSGP's vulnerability to the climate crisis was high in the order of drought, heat wave, heavy rain and strong wind. As a drought adaptation measure, policies of water saving and revenue water ratio improvement were considered. As for the heat wave adaptation measure, the introduction of an advanced water treatment process was suggested in response to the increase of algae cell number which resulting in taste and odor problem. As for heavy rain adaptation measures, the installation and operation of automatic coagulant injection devices for water purification plants that take turbid surface water were proposed. As a measure to adapt to strong winds, stabilization of power supply such as installation of dual power line was proposed in preparation for power outages. It is expected that water facilities will be able to supply high-quality tap water to customers even under extreme climate conditions without interruption through risk assessment for climate crisis factors and active implementation of adaptation measures.