• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2806-2811
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• 2013

New technologies such as multi-antenna and small cell were proposed as key technology for the next generation mobile system to cope with the explosively increasing mobile data traffic. In particular, heterogeneous mobile communication network which can improve spatial reuse factor by exploiting macro and small cells simultaneously is attracting attention. However, the heterogeneous network has a problem that the utilization of small cells becomes low because the transmit power of macro base stations is much higher than that of small base stations and then the probability that mobile stations are attached to the macro base stations becomes high. This problem is dominant in uplink. The concept of cell range expansion bias to mitigate the problem was proposed by 3GPP and the corresponding standardization is in progress. In this paper, we analyze the downlink performance of the heterogeneous mobile communication network based on a system level simulator with the cell range expansion bias in terms of average cell spectral efficiency.

• 발명특허
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• v.10 no.10 s.116
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• pp.18-24
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• 1985

한국발명특허협회는 기업의 적극적인 참여와 관계당국의 지원을 받아 지난 73년 10월 18일 창립, 그간 발명 및 공업소유권관계 제위의 아낌없는 성원에 힘입어 금년 10월 18일로 12주년을 맞게 되었다. 창립당시 우리나라는 선진국으로 도약하기 위하여 경제개발과 수출드라이브 정책을 추구하기 위해 창조적 자주기술 개발과 선진기술을 도입, 소화흡수하는 것의 시급한 문제로 대두되었으며 더욱이 앞으로 다가올 본격적인 국제화 시대와 자유경쟁시대에 대비하여 외국과의 경쟁에서 이길 수 있는 산업기반의 구책이 절실했다. 이러한 시대적 요청에 부응하기 위하여는 공업소유권 제도의 확립을 통한 신기술 개발의 촉진 및 발명풍토조성이 선결 문제였으며 이를 해결코자 본회가 창립되었던 것이다. 이에 창립과 동시 공업소유권 제도의 수용태세를 갖추도록 하기 위하여 그 인식제고와 보급$\cdot$확산을 통한 제도 정착에 노력해 왔다. 그 결과 동제도의 불모지였던 우리나라 산업계에서도 공업소유권 제도에 눈을 뜨기 시작했으며 ${\ulcorner}$66발기회원${\lrcorner}$으로 출발하였던 본회는 이제 320회원에 이르게 되었다. 또 공업소유권 제도에 대한 인식을 바탕으로 발명$\cdot$신기술개발을 적극적으로 유도하기 위해 발명특허 정보의 보급에 힘써 왔으며 이에따라 기업 및 발명인들이 우수한 발명품들을 창안하여 기업화함으로써 국내 공급은 물론 수출까지 하는 사례도 많이 늘게 되었다. 그러나 무엇 보다도 획기적인 전환점은 지난 82년 한국특허협회를 한국발명특허협회로 확대 개편한데있다. 전경환 명예회장$\cdot$구자경 회장$\cdot$이태섭 상근부회장을 주축으로 재출범한 본회는 지난 4년동안 기술국립으로 지향하는 국가시책에 부응하는 기술혁신의 요체가 되는 공업소유권제도의 정착과 발명환경 조성을 위한 사업기본방향을 공업소유권 인식제고$\cdot$발명진흥장려$\cdot$특허관리체제확립 등 3대 목표에 두고 발명특허의식고양사업$\cdot$공업소유권관리요원양성배출사업$\cdot$발명진흥행사 및 전시사업$\cdot$발명지원사업$\cdot$발명보호계도사업$\cdot$공업소유권제도조사연구사업$\cdot$공업소유권관리자료발간 보급사업$\cdot$각종 공보발간사업$\cdot$발명특허자료(책자)판매선터운영 등 중점사업을 전개하여 이제 명실상부한 국내 유일의 공업소유권 단체로 도약해가고 있다. 발명의 날 부활에 따른 기념행사를 통한 발명유공자 및 우수특허관리기업체 포상, 전국우수발명품 전시회 개최, 발명시작품제작보조, 발명장려관 설치운영, 해외출원비용 및 해외발명전 출품지원등 발명진흥장려사업에 새로운 전기를 마련한 것이다. 한 마디로 ${\ulcorner}$0년이면 강산도 변한다${\lrcorner}$는 속언을 실감하게 한다. 창립 12주년! 이제 또다시 변해가는 시점에서 지난 12년사를 20대 뉴스를 중심으로 소개한다.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.471-480
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• 2016

Recently, the damage of cyber attack toward infra-system, national defence and security system is gradually increasing. In this situation, military recognizes the importance of cyber warfare, and they establish a cyber system in preparation, regardless of the existence of threaten. Thus, the study of Intrusion Detection System(IDS) that plays an important role in network defence system is required. IDS is divided into misuse and anomaly detection methods. Recent studies attempt to combine those two methods to maximize advantagesand to minimize disadvantages both of misuse and anomaly. The combination is called Hybrid IDS. Previous studies would not be inappropriate for near real-time network environments because they have computational complexity problems. It leads to the need of the study considering the structure of IDS that have high detection rate and low computational cost. In this paper, we proposed a Hybrid IDS which combines C4.5 decision tree(misuse detection method) and Weighted K-means algorithm (anomaly detection method) hierarchically. It can detect malicious network packets effectively with low complexity by applying mutual information and genetic algorithm based efficient feature selection technique. Also we construct upgraded the the hierarchical structure of IDS reusing feature weights in anomaly detection section. It is validated that proposed Hybrid IDS ensures high detection accuracy (98.68%) and performance at experiment section.

• Korean Security Journal
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• no.28
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• pp.57-77
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• 2011

Recently, property and life loss is increasing internally and externally, due to fire spread in high-rise buildings which results from a variety of disasters like fire and terror. In this study, therefore, an evacuation simulation was performed to predict escape behaviors of occupants and assess escape safety in high-rise office buildings after setting up each scenario, as part of safety measures for high-rise buildings. Based on the results and data obtained, escape safety was assessed, finally. The results and suggestions of this study are as follows. Firstly, most of the present researches on high-rise building and multiple-use facilities are weighted towards qualitative perspectives. It is, therefore, considered that we have to establish concrete, practical, systematical and rational safety measures to minimize damages in dangerous situations, by analyzing security plans for high-rise buildings in depth and preparing for those situations from various angles. Secondly, setting up evacuation sections in security plans for high-rise buildings is an important factor which influences refuge. Thirdly, in relation to security plans for high-rise buildings, it is possible to reduce the entire time for escape, by setting up escape exits of each floor in consideration of a simultaneous evacuation situation.

• Membrane Journal
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• v.25 no.6
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• pp.496-502
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• 2015

Facilitated transport is one of the possible solutions to simultaneously improve permeability and selectivity, which is challenging in conventional polymer-based membranes. Olefin/paraffin separation using facilitated transport membrane has received much attention as an alternative solution to the conventional distillation process. Herein, we report olefin separation composite membranes based on the polymer blends containing $AgBF_4/Al(NO_3)_3$ mixed salts. Free radical polymerization process was used to synthesize an amphiphilic graft copolymer of poly(dimethyl siloxane)-graft- poly(ethylene glycol) methyl ether methacrylate (PDMS-g-POEM). In addition, poly(ethylene oxide) (PEO) was introduced to the PDMS-g-POEM graft copolymer to form polymer blends with various ratios. The propylene/propane mixed-gas selectivity and permeance reached up to 5.6 and 10.05 GPU, respectively, when the PEO loading was 70 wt% in polymer blend. The improvement of olefin separation performance was attributed to the olefin facilitating silver ions as well as the highly permeable blend matrix. The stabilization of silver ions in the composite membrane was achieved through the introduction of $Al(NO_3)_3$ which suppressed the reduction of silver ions to silver particles.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.584-591
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• 2017

Metal removal from water has not been explained clearly by either adsorption onto the surface of absorbents or precipitation as metal hydroxides because those occur simultaneously to a certain extent. For a better understanding of the metal removal mechanisms, batch experiments were performed using soil calcined at $850^{\circ}C$ under various pH conditions for Cu, Pb, Zn, Cd, and Cr. The results showed that the metal removal efficiency with the exception of Cr decreased abruptly, even within 5 min, showing more than 90% removal. The pH of each reactant increased gradually from around 7 to 9 with time. The increases in metal removal at higher pH appear to be associated with metal hydroxides precipitation. Comparative experiments, which were carried out changing the pH by reacting with commercial activated carbon (CAC), natural yellow soil (NYS), and calcined yellow soil (CYS), showed that the pH of the CYS only increased with time. Calcination processes might lead to a change in the physical properties of the soil matrix resulting in a high pH when reacted with water. Apart from adsorption onto the surface of the absorbents, these results show that the adsorption and/or precipitation of hydroxides onto the surface of adsorbents also play important roles in regulating the dissolved metals under alkaline conditions.

• Resources Recycling
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• v.25 no.6
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• pp.13-22
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• 2016

This study is aimed at compare and evaluate the environmental impact of End-of-Life Vehicle(ELV) on the eco-friendly technology dismantling and recycling system, using Life Cycle Assessment (LCA) method. In this study, it was analyzed for the environmental impacts of raw materials, disassemble process, recycle parts separation and waste treatment into the process of ELV treatment by greenhouse gas and resource consumption, etc. Through this study, the indoor rail type dismantling technology were recycling rate applied on the alternate system was increased by approximately 8%. As a result, it was 3 to 88% by improving the environmental impact category. In addition, the added benefit of approximately 8 - 62% in pre-market occurred through the recycling rate, improve parts reuse rate of ELV. Through the results of this study, legal compliance, improved reuse and recycling ratio, used parts market reach, enable exports has identified the need for the effort that the dissemination and diffusion of eco-friendly technology.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.62-70
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• 2015

Recently the demand for projected capacitance touch screens is sharply growing especially for large screens for medical devices, PC monitors and TVs. Large touch screens in general need a controller of higher complexity. They usually have a larger number of driving and sensing lines, and hence it takes longer to scan one frame for touch detection leading to a low frame scan rate. In this paper, a novel touch screen control technique is presented, which scans each frame in two steps of simultaneous multi-channel driving. The first step is to drive all driving lines simultaneously and determine which sensing lines have any touch. The second step is to sequentially rescan only the touched sensing lines, and determine exact positions of the touches. This technique can substantially increase the frame scan rate. This technique has been implemented using an FPGA and an AFE board, and tested using a commercial 23-inch touch screen panel. Experimental results show that the proposed technique improves the frame scan rate by 8.4 times for the 23-inch touch screen panel over conventional methods.

• Resources Recycling
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• v.28 no.5
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• pp.51-59
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• 2019

This study focused on the synthesis of the nickel hydroxide using ammonium sulfate in leaching solution from waste nickel-cadmium batteries. The effect of pH, temperature and the input amount of ammonium sulfate in leaching solution was investigated. The ammonium nickel sulfate with high purity was obtained in acidic leaching solution and the solution temperature of $60^{\circ}C$. The suitable molar ratio of the input amount of ammonium sulfate to nickel in solution is 2:1. The impurity about 1.4 at.% of Cd was included in the nickel hydroxide precipitates when ammonium nickel sulfate was used. At the process using sodium sulfide which precipitates the cadmium in solution, nickel and iron compounds were precipitated together.

• Composites Research
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• v.34 no.5
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• pp.283-289
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• 2021

This paper derives numerically the buckling Knockdown factors using two different initial imperfection models, such as geometric and loading imperfection models, to investigate the unstiffened composite cylinder with an ellipse pre-buckling deformation pattern. Single Perturbation Load Approach (SPLA) is applied to represent the geometric initial imperfection of a thin-walled composite cylinder; while Single Boundary Perturbation Approach (SBPA) is used to represent the geometric and loading imperfections simultaneously. The buckling Knockdown factor derived using SPLA is higher than NASA's buckling design criteria by approximately 84%, and lower than buckling test result by 9%. The buckling Knockdown factor using SBPA is higher than NASA's buckling design criteria by about 75%, and 14% lower than the buckling test result. Therefore, it is shown that the buckling Knockdown factors derived in this study can provide a lightweight design compared to the previous buckling design criteria while they give reasonably a conservative design compared to the buckling test for both the initial imperfection models.