• 한국군사과학기술학회지
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• 제24권5호
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• pp.537-544
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• 2021

Cyber threats can bypass existing cyber-protection systems and are rapidly developing by exploiting new technologies such as artificial intelligence. In order to respond to such cyber threats, it is important to improve the ability to detect unknown cyber threats by correlating heterogeneous cyber protection systems. In this paper, to enhance cyber-attack response capabilities, we proposed command and control that enables rapid decision-making and response before the attack objectives are achieved, using Lockheed Martin's cyber kill chain and MITRE ATT&CK to analyze the purpose and intention of the attacker.

• ETRI Journal
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• 제43권2호
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• pp.173-183
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• 2021

As low-power wide-area network (LPWAN) end devices (EDs) are deployed in massive scale, their economic and environmental costs of operation are becoming too significant to ignore and too difficult to estimate. While LPWAN architectures and protocols are designed to primarily save energy, this study shows that energy saving does not necessarily lead to lower cost or environmental footprint of the network. Accordingly, a theoretical framework is proposed to estimate the operational expenditure (OpEx) and environmental footprint of LPWAN EDs. An extended constrained optimization model is provided for the ED link assignment to gateways (GWs) based on heterogeneous ED configurations and hardware specifications. Based on the models, a simulation framework is developed which demonstrates that OpEx, energy consumption, and environmental footprint can be in conflict with each other as constrained optimization objectives. We demonstrate different ways to achieve compromises in each dimension for overall improved network performance.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.439-444
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• 2011

As construction projects have been getting larger and more complex, a single individual or organization cannot have complete knowledge or the abilities to handle all matters. Collaborative practices among heterogeneous individuals, which are temporarily congregated to carry out a project, are required in order to accomplish project objectives. These organizational knowledge creation processes of project teams should be understood from the active and dynamic viewpoint of how they create information and knowledge rather than from the passive and static input-process-output sequence. To this end, agent-based modeling and simulation which is built from the ground-up perspective can provide the most appropriate way to systematically investigate them. In this paper, agent-based modeling and simulation as a research method and a medium for representing theory is introduced. To illustrate, an agent-based simulation of the evolution of collaboration in large-scale project teams from a game theory and social network perspective is presented.

• Asian-Australasian Journal of Animal Sciences
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• 제24권1호
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• pp.17-27
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• 2011

A selection experiment for reduced residual feed intake (RFI) in Yorkshire pigs consisted of a line selected for lower RFI (LRFI) and a random control line (CTRL). Longitudinal measurements of daily feed intake (DFI) and body weight (BW) from generation 5 of this experiment were used. The objectives of this study were to evaluate the use of random regression (RR) and nonlinear mixed models to predict DFI and BW for individual pigs, accounting for the substantial missing information that characterizes these data, and to evaluate the effect of selection for RFI on BW and DFI curves. Forty RR models with different-order polynomials of age as fixed and random effects, and with homogeneous or heterogeneous residual variance by month of age, were fitted for both DFI and BW. Based on predicted residual sum of squares (PRESS) and residual diagnostics, the quadratic polynomial RR model was identified to be best, but with heterogeneous residual variance for DFI and homogeneous residual variance for BW. Compared to the simple quadratic and linear regression models for individual pigs, these RR models decreased PRESS by 1% and 2% for DFI and by 42% and 36% for BW on boars and gilts, respectively. Given the same number of random effects as the polynomial RR models, i.e., two for BW and one for DFI, the non-linear Gompertz model predicted better than the polynomial RR models but not as good as higher order polynomial RR models. After five generations of selection for reduced RFI, the LRFI line had a lower population curve for DFI and BW than the CTRL line, especially towards the end of the growth period.

• Journal of Preventive Medicine and Public Health
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• 제50권6호
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• pp.401-410
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• 2017

Objectives: The purpose of this study was to examine the associations of childbirth, breastfeeding, and their interaction with breast cancer (BC) risk reduction, and to evaluate the heterogeneity in the BC risk reduction effects of these factors by menopause, hormone receptor (HR) status, and pathological subtype. Methods: BC patients aged 40+ from the Korean Breast Cancer Registry in 2004-2012 and controls from the Health Examinee cohort participants were included in this study after 1:1 matching (12 889 pairs) by age and enrollment year. BC risk according to childbirth, breast-feeding, and their interaction was calculated in logistic regression models using odds ratios (ORs) and 95% confidence intervals (CIs). Results: BC risk decreased with childbirth (3+ childbirths relative to 1 childbirth: OR, 0.66; 95% CI, 0.56 to 0.78 and OR, 0.80; 95% CI, 0.68 to 0.95 in postmenopausal and premenopausal women, respectively); and the degree of risk reduction by the number of children was heterogeneous according to menopausal status (p-heterogeneity=0.04), HR status (p-heterogeneity<0.001), and pathological subtype (p-heterogeneity<0.001); whereas breastfeeding for 1-12 months showed a heterogeneous association with BC risk according to menopausal status, with risk reduction only in premenopausal women (p-heterogeneity<0.05). The combination of 2 more childbirths and breastfeeding for ${\geq}13$ months had a much stronger BC risk reduction of 49% (OR, 0.51; 95% CI, 0.45 to 0.58). Conclusions: This study suggests that the combination of longer breastfeeding and more childbirths reduces BC risk more strongly, and that women who experience both 2 or more childbirths and breastfeed for ${\geq}13$ months can reduce their BC risk by about 50%.

• 한국산학기술학회논문지
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• 제21권7호
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• pp.12-19
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• 2020

클러스터된 이기종 무선 센서 네트워크는 서로 다른 목적을 가지는 노드들이 계층적 구조를 이루어 링크를 구성하는 네트워크를 의미한다. 무선 센서 네트워크에서는 한정적인 메모리나 배터리 용량 내에서 운용되는 경우가 많기 때문에 이러한 자원을 효율적으로 관리해야만 네트워크의 수명, 커버리지, 연결성 등의 성능을 길게 유지할 수 있다. 예를 들어 특정 센서들의 부근에서 관심을 가지는 이벤트가 빈번하게 발생하여 계측되는 데이터가 증가하게 되면, 특정 클러스터 그룹의 클러스터 헤드로 전송되는 데이터의 양도 동시에 기하급수적으로 증가하게 된다. 특히 해당 클러스터 헤드에서 전송하는 데이터양보다 센서들로부터 수신하는 데이터양이 많을 경우나 링크가 끊어져 데이터 전송이 불가능한 경우 메모리 총 용량을 초과하는 데이터 혼잡 문제가 발생한다. 본 논문에서는 이러한 데이터 혼잡 문제를 해결하기 위해 모바일 싱크로서 드론을 이용한다. 네트워크, 센서 노드, 클러스터 헤드에 대한 모델링 후 데이터 혼잡도를 계산하기 위한 비용 함수와 혼잡 인디케이터를 정의한다. 이를 바탕으로 데이터 혼잡 지도 인덱스를 계산하여 데이터 혼잡 지도를 작성 후 지도를 기반으로 드론을 최적의 위치에 배치한다. 시뮬레이션을 통하여 드론의 배치에 따른 네트워크의 혼잡도가 감소하는 양상을 다양한 접근을 통해 보여준다. 제어 변수 α를 이용하여 배치되는 드론 수에 따른 데이터 혼잡도의 변화, 요구하는 데이터 혼잡도를 만족시키기 위한 통신 범위와 드론 수와의 관계를 알아본다. 또한 기존 연구와의 오버플로우 관점에서 비교를 통해 제안하는 알고리즘이 최소 20 %의 향상이 있음을 보여준다.

• 디지털콘텐츠학회 논문지
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• 제12권4호
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• pp.501-510
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• 2011

다양한 의료서비스를 정형화되고 효율적인 방법으로 제공하기 위하여 최근 의료기관의 전자의무기록 시스템의 도입이 활발하다. 그러나 국내에서 개발된 대부분의 전자의무기록시스템은 자료수집원 기반의 방식으로 개발되어 왔다. 이러한 시스템들은 시스템 아키텍처와 소프트웨어 프로세스의 태생적인 한계로 인해 전자의무기록시스템의 도입이 추구하는 다양한 목표를 충족시키지 못하고 있다. 이러한 한계를 극복하기 위해 본 연구는 수집원 지향 방식으로 획득한 의무기록 콘텐츠와 문제지향 방식으로 획득한 의무기록 콘텐츠를 융합할 수 있는 시스템 아키텍처와 이러한 시스템을 구축하기 위한 최적화된 소프트 웨어 프로세스를 제시하였다. 이를 위해 문제지향식 의무기록 생성을 위한 진료 과정과 데이터 요구사항을 분석한 후 진료데이터저장소, 문제목록 데이터베이스, 동기화 모듈 등으로 구성되는 아키텍처와 나선형 소프트웨어 프로세스를 제시하고 프로토타입을 개발하였다.

• 대한원격탐사학회지
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• 제27권6호
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• pp.625-635
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• 2011

This paper investigates the effects of spatial autocorrelation structures in low resolution data on downscaling without ground measurements or secondary data, as well as the potential of geostatistical downscaling. An advanced geostatistical downscaling scheme applied in this paper consists of two analytical steps: the estimation of the point-support spatial autocorrelation structure by variogram deconvolution and the application of area-to-point kriging. Point kriging of block data without variogram deconvolution is also applied for a comparison purpose. Experiments using two low resolution thematic maps derived from remote sensing data showing very different spatial patterns are carried out to discuss the objectives. From the experiments, it is demonstrated that the advanced geostatistical downscaling scheme can generate the downscaling results that well preserve overall patterns of original low resolution data and also satisfy the coherence property, regardless of spatial patterns in input low resolution data. Point kriging of block data can produce the downscaling result compatible to that by area-to-point kriging when the spatial continuity in block data is strong. If heterogeneous local variations are dominant in input block data, the treatment of the low resolution data as point data cannot generate the reliable downscaling result, and this simplification should not be applied to donwscaling.

• Computers and Concrete
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• 제17권1호
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• pp.107-127
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• 2016

Concrete is a heterogeneous material containing many weaknesses such as micro-cracks, pores and grain boundaries. The crack growth mechanism and failure behavior of concrete structures depend on the plastic deformation created by these weaknesses. In this article the non-linear finite element method is used to analyze the effect of presence of micro pore near a crack tip on both of the characteristics of crack tip plastic zone (its shape and size) and crack growth properties (such as crack growth length and crack initiation angle) under pure shear loading. The FE Code Franc2D/L is used to carry out these objectives. The effects of the crack-pore configurations and the spacing between micro pore and pre-excising crack tip on the characteristics of crack tip plastic zone and crack growth properties is highlighted. Based on the obtained results, the relative distance between the crack tip and the micro pore affects in very significant way the shape and the size of the crack tip plastic zone. Furthermore, crack growth length and crack initiation angle are mostly influenced by size and shape of plastic zone ahead of crack tip. Also the effects of pore decrease on the crack tip by variation of pore situation from linear to perpendicular configuration. The critical position for a micro pore is in front of the crack tip.

• 한국IT서비스학회지
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• 제5권2호
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• pp.107-123
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• 2006

The objectives of this study is to develop a strategy for the adoption of BPM(Business Process Management) standards and an implementation guideline of the BPM standard for BPM solution developers focusing on BPEL(Business Process Execution Language) which is regarded as the most important BPM standard. In the heterogeneous and distributed IT environments, every type of enterprise software requires standards to enhance interoperability. BPMS(Business Process Management System), which is a type of enterprise software requires BPM standards such as BPEL(Business Process Execution Language), BPMN(Business Process Modeling and Notation), BPQL(Business Process Query Language) and so on to achieve multi-system interoperability and component interoperability with their BPM solutions. It is quite helpful to provide the adoption strategy concerning BPM standards for each type of BPM solution vendors who need the BPM standards. Since the BPEL is conceived as the most important BPM standard and widely adopted by many BPM vendors, we have proposed a reference architecture for BPEL implementation and also developed the detail implementation guideline of core components of the BPM system supporting the BPEL standard. Using the strategy and implementation guideline proposed in this work, BPM solution vendors can establish their own standard adoption strategy and they can also develop their BPM solutions supporting the BPM standards more efficiently.