• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.274-274
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• 2022

확률론적 지진해일 재해도 평가(PTHA)는 최근 지진해일에 대한 연구에서는 관심을 많이 받고 있는 주제로 여러 국가에서 연구가 진행되고 있다. 단층매개변수의 민감도 분석은 일본(Goda et al., 2014), 미국(Sepúlveda and Liu, 2016), 뉴질랜드(D. Burbridge et al., 2015) 등에서 연구가 활발하게 이루어졌으며 현재도 활발한 연구가 진행되고 있다. 민감도 분석은 PTHA를 진행하기 위한 선행 과정으로 파향선 추적을 통한 대상지 설정 및 연구 대상 단층을 선정한 후 로직트리를 만들기 위해 각 단층 매개변수의 범위와 단위 폭을 제시한다. 해당 연구는 세 가지 단층 매개변수에 대한 지진해일 초기파와 파고에 대한 민감도 분석을 실행했다. 주향각은 초기파와 지진해일고에 대해서 임의의 변동을 보이지만 변동 폭은 다른 두 매개변수들과 비교하여 가장 크다. 경사각과 슬립각은 단층의 수직 움직임을 변화시키며 이를 통해 초기파의 변동을 예측할 수 있다. 초기파의 변동과 모양을 분석함으로써 수치 계산이 가설과 유사한 결과를 보임을 확인하였다. 경사각과 슬립각에 의한 지진해일고의 변화는 최저 지진해일고가 초기파의 총 에너지와 연관된다는 결론에 이른다. 지진해일 재해도는 해안지역에 도달하는 최종 파고와 관련이 있으므로 각 매개변수의 단위 폭은 지진해일고의 결과를 통해 선정되었다. 민감도 분석은 제시한 주향각, 경사각, 슬립각의 단위 폭을 이용하여 로직트리의 분기 수를 감소시켜 수치 계산 시간을 줄임으로써 PTHA의 효율성을 증대시킨다.

• Journal of Science and Technology Studies
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• v.16 no.1
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• pp.29-61
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• 2016

This paper explains the one of the most problematic factor in the society that leads to social inequality - increase in non-regular work. Theoretically, this expansion of non-regular work can be explained by technologies that are designed to save the labor force, especially since corporations in Korea have strategies to replace the regular workers with temporary workers, to save money. OECD also noted that Korea's income inequality is pretty high in ranking when compared with the rest of the OECD members, and says that globalization and technological innovation are the factors of this problem. To refine the argument, this study also looks at relationship between development made in sciences - which can be stated as a proxy variable to look at the advances made in technology - and expansion of temporary work force by using VAR methodology. Based on the results of this analysis in the future temporary/regular workers ratio started with decline, then turn to rise. These temporary/regular workers ratio sustained growth prediction shows that the expansion of the temporary expansion contributes to instability and social inequality in the labor market and technological change are interrelated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.831-841
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• 2010

The conventional vertical probe has the thin and long signal path that makes transfer characteristic of probe worse because of the S-shaped structure. So we propose the new vertical probe structure that has branch springs in the S-shaped probe. It makes closed loop when the probe mechanically connects to the electrode on a wafer. We fabricated the proposed vertical probe and measured the transfer characteristic and mechanical properties. Compared to the conventional S-shaped vertical probe, the proposed probe has the overdrive that is 1.2 times larger and the contact force that is 2.5 times larger. And we got the improved transfer characteristic by 1.4 dB in $0{\sim}10$ GHz. Also we developed the simulation model of the probe card by using full-wave simulator and the simulation result is correlated with measurement one. As a result of this simulation model, the cantilever probe and PCB have the worst transfer characteristic in the probe card.

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.5
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• pp.101-106
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• 2020

Since computer became available, much effort has been made to achieve information security. Even though memory protection defense mechanisms were studied the most among of them, the problems of existing memory protection defense mechanisms were found due to improved performance of computer and new defense mechanisms were needed due to the advent of the side-channel attacks. In this paper, we propose JMP+RAND that embedding random values of 5 to 8 bytes per page to defend against memory sharing based side-channel attacks and bridging the gap of existing memory protection defense mechanism. Unlike the defense mechanism of the existing side-channel attacks, JMP+RAND uses static binary rewriting and continuous jmp instruction and random values to defend against the side-channel attacks in advance. We numerically calculated the time it takes for a memory sharing-based side-channel attack to binary adopted JMP+RAND technique and verified that the attacks are impossible in a realistic time. Modern architectures have very low overhead for JMP+RAND because of the very fast and accurate branching of jmp instruction using branch prediction. Since random value can be embedded only in specific programs using JMP+RAND, it is expected to be highly efficient when used with memory deduplication technique, especially in a cloud computing environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1537-1540
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• 2009

홍수통제소는 수문조사, 하천유량관리, 홍수예보 등 다양한 업무를 수행하고 있다. 수문조사는 물 관리를 위한 기본 자료 확보와 수자원이라는 국가의 귀중한 자산을 정량화하는 중요한 업무이다. 하천유량 관리는 하천의 물을 합리적으로 관리하여 공익을 증진하고 모든 사람들이 혜택을 고루 향유할 수 있도록 배분하는 업무이다. 홍수예보는 큰 비에 의해 유역에서 발생할 수 있는 홍수의 규모를 예측하고 그 수치를 유관기관에 제공하여 홍수를 사전에 대비토록 함으로써 홍수피해를 최소화 할 수 있도록 하는 업무이다. 상기 언급된 홍수통제소의 주요 업무들을 효율적으로 수행하기 위하여 낙동강홍수통제소에서는 전년도 시험연구과제로서 "홍수통제소 발전방안"이라는 주제로 낙동강 홍수통제소의 발전을 위한 기본적인 개선항목 중 홍수통제소 홍보동영상 제작을 통한 통제소 홍보 및 이미지 제고, 수자원 자료실의 전산화와 관측소 이력 및 기본제원 시스템화 등을 통한 업무의 효율성 증대를 위하여 연구를 수행하였다. 금년은 지난해 개선된 업무들을 토대로 업무 효율성 증대를 도모하고자 한다. 현재 낙동강홍수 통제소에서 관리되고 있는 수문관측소는 239개소(수위 및 우량, 10분 단위)으로, 이들 관측소에 대한 효율적인 관리와 정확한 자료 생성을 위해서는 해당 내용에 대한 체계적이고 합리적인 관리가 필요하다. 이를 위하여 관측소 이력관리 프로그램을 시험적으로 운영을 하여 매년 실시되는 분기별 관측소 정기점검 결과를 업로드 시켜 관련 직원들이 내용을 공유할 수 있도록 추진하고 있다. 이는 수문자료의 정확한 검보정에도 활용될 수 있을 뿐만 아니라 다양한 정보를 체계적으로 관리하여 향후 추가적인 업무 효율화를 위하여도 이용될 수 있을 것이다.

• KIISE Transactions on Computing Practices
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• v.23 no.8
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• pp.498-503
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• 2017

SIMD (Single Instruction Multiple Data) is a representative parallelization architecture that processes multiple data loaded in a SIMD register with a single instruction. Quicksort is a sorting algorithm that picks an element as a pivot from the array and reorders the array such that all elements having the values less than the pivot value are located in the left side on the pivot as well as all elements having the value greater than the pivot value are located in the right side on the pivot and then the algorithm performs the same task on both sublist recursively. In this paper, we propose an efficient Quicksort algorithm applying the SIMD instructions which minimally invokes conditional branches to avoid the performance degradation incurred by branch misprediction in a pipeline architecture. In addition, we improve the performance of the Quicksort algorithm by fetching data into a SIMD register as a byte unit to apply VBP (Vertical Bit Parallel) and the early pruning technique.

• The Journal of the Convergence on Culture Technology
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• v.3 no.2
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• pp.43-48
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• 2017

5G will bring revolutionary development in mobile communication, and it is anticipated to have complete commercialization including mass adoption rate by 2020s. High number of smart devices including IoT, wearable devices, etc., which have high amount of data usage, will involve even higher data traffics. In addition, media dependency and demand is rapidly rising. These environmental aspects will necessity and sufficient condition for successful implementation of 5G mobile communication system. In this paper, global cooperation and competition for 5G technology leadership will be analyzed and summarized. Through this, proper solution to maintain competency of Korea in future will be proposed.

• The Korean Journal of Applied Statistics
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• v.26 no.3
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• pp.441-452
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• 2013

This study analyzed the relationship between key film and a box office record success factors based on movies released in the first quarter of 2013 in Korea. An over-fitting problem can happen if there are too many explanatory variables inserted to regression model; in addition, there is a risk that the estimator is instable when there is multi-collinearity among the explanatory variables. For this reason, optimal variable selection based on high explanatory variables in box-office performance is of importance. Among the numerous ways to select variables, LASSO estimation applied by a generalized linear model has the smallest prediction error that can efficiently and quickly find variables with the highest explanatory power to box-office performance in order.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.4
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• pp.135-141
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• 2020

Today, CPUs in general-purpose computers such as servers, desktops and laptops, as well as home appliances and embedded systems, consist mostly of multicore processors. In order to improve performance, it is required to use an out-of-order execution processor by Tomasulo algorithm as each core processor. An out-of-order execution processor with Tomasulo algorithm can execute the available instructions in any order and perform speculation in order to reduce control dependencies. Therefore, the performance of an out-of-order execution processor can be significantly improved compared to an in-order execution processor. In this paper, an out-of-order execution processor using Tomasulo algorithm and ARM instruction set is designed using VHDL record data types and simulated by GHDL. As a result, it is possible to successfully perform operations on programs written in ARM instructions.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.3
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• pp.277-289
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• 2005

The study examines the limit strength for steel cable-stayed bridges. A case studies have been performed in order to evaluate the limit strength lot steel cable-stayed bridges using nonlinear inelastic analysis approach and bifurcation point instability analysis approach, effective tangent modulus $(E_f)$ method. To realize it, a practical nonlinear inelastic analysis condoling the initial shape is developed. In the initial shape analysis, updated structural configuration is introduced instead of initial member forces for beam-column members at every iterative step. Geometric and material nonlinearities of beam-column members are accounted by using stability function, and by using CRC tangent modulus and parabolic function, respectively Besides, geometric nonlinearity of cable members is accounted by using secant value of equivalent modulus of elasticity. The load-displacement relationships obtained by the proposed method are compared well with those given by other approaches. The limit strengths evaluated by the proposed nonlinear inelastic analysis for the proposed cable-stayed bridges with tee dimensional configuration compared with those by the inelastic bifurcation point instability analyses.