• Journal of the Korean School Mathematics Society
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• v.19 no.4
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• pp.441-457
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• 2016

The purpose of this study is to analyze Korean students' mathematics achievement characteristics and draw implications for better math education in schools through comparing the results of three east Asian top level countries, Korea, Singapore, and Japan in PISA 2012 results. As a results, the rate of correct answers of Korea students was relatively low compared with those of Singapore, but relatively higher than Japan. From the results of effect size, similar results from t-test was discovered. As shown in analysis according to sub-elements in math assessment framework, the Korean students had low effect size in every sub-elements than Singapore. and they had high effect size at most of sub-elements than Japan, except "personal" context. In top performing level(above level 5), the Korean students had high effect size at "quantities" in mathematical contents, and "employ" in mathematical processes compared with Singapore. And they had row effect size at 6 sub-elements compared with Japan.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.209-220
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• 2016

Although organizations are providing information security policy, education and support to guide their employees in security policy compliance, accidents by non-compliance is still a never ending problem to organizations. This study investigates the factors that influence employees' information security policy compliance behavior using elements of Triandis model. We analyzed the relationships among Triandis model's factors using PLS(Partial Least Squares). The result of the hypothesis tests shows that organization can induce individual's information security policy compliance intention and behavior by information security policy and facilitating conditions that support it, and proves the importance of members' expected value, habit and affect about information security compliance. This study is significant in a way that it applies Triandis model in the field of information security, and presents direction for members' information security behavior, and will be able to provide measures to establish organization's information security policy and increase members' compliance behavior.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.423-429
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• 2011

Cooperative spectrum sensing is proposed to overcome some problem such as multipath fading and shadowing and to improve spectrum sensing performance. There are different combining methods for cooperative spectrum sensing: hard decision method and soft decision method. In this paper, we analysis the performance of cooperative spectrum sensing with distance based weight that is kind of a soft decision rule for cognitive radio(CR) systems and CR systems sense the spectrum of the licensed user by using a energy detection method. Threshold is determined in accordance with the constant false alarm rate(CFAR) algorithm for energy detection. The signal of licensed user is OFDM signal and the wireless channel between a licensed user and CR systems is modeled as Gaussian channel. From the simulation results, the cooperative spectrum sensing with distance based weight combining(DWC) and equal gain combing(EGC) methods shows higher spectrum sensing performance than single spectrum sensing does. And the detection probability performance with the DWC is higher than that with the EGC.

• Fire Science and Engineering
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• v.25 no.6
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• pp.127-135
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• 2011

In this study, we assumed the kitchen fire raising the highest fire rate in apt. and analyzed the fire risk to use CFD in order to estimate the problem of evacuation equipment and the fire vulnerability of 16 or fewer storey apartment. Fire occurring in the kitchen is expended to the livingroom and other rooms. We analyzed that the temperature effected by heat was more than $60^{\circ}C$ after 90 sec in the entrance of apartment unit. If fire is early recognized by men and men don't escape in time, it have too huge demage to block the exit. When the evacuation equipment suggested in this study was installed in order to solve the problem of evacuation equipment, we analyzed that it was estimated more than safe in safety evaluation by heat and heat flux.

• 한국IT서비스학회:학술대회논문집
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• 2008.11a
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• pp.535-540
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• 2008

It is a fact that we are yet to recognize and sense the U-City even though the business of U-City construction has been started many years ago. One of the causes is that UCity was thoughtlessly developed in the industry-centered environment for a tangible achievement, despite of need on more systematic development and organized management. Fortunately, it is expected that the most part of the situation will be solved, since "laws on the construction of the ubiquitous city" for planning, construction and management has been promulgated on March, and U-City project will be systematically promoted by the related laws from now. Therefore, intention of this study is the sustainable development of the U-City by analyzing the previous process and problems of the U-City Construction project of local governments and reengineering U-City construction project process in accordance with new laws, using the BPR methodology.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.37-49
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• 2008

Services are reusable units in business level. Ubiquitous computing provides computing services anytime and anywhere. The combination of both is becoming an important paradigm of computing environment. Fundamentals of services require flexibility and interoperability, and key elements of ubiquitous modeling require interoperability and context-awareness. There are two kinds of methods to identify services. The top-down approach is based on business process, and the bottom-up approach is based on components. The first approach depends on experts' intuitions, while the second approach suffers the incapability of expressing non-functional expression through components. Although a feature-based approach is capable of expressing non-functional expression and identifying services in ubiquitous environment, the research on this issue is not adequately addressed by far. To promote this research, this paper proposes a feature-based method to identify services in ubiquitous computing. The method extracts initial-candidate-services from a feature model. Then, the ultimate services are identified through optimizing and analyzing the candidate-services. The proposed method is expected to enhance the service reusability by effectively analyzing ubiquitous domain based on feature, and varying reusable service units.

• Journal of IKEEE
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• v.21 no.4
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• pp.338-347
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• 2017

This paper describes the design and fabrication of a high power amplifier which is a component of TDL(Tactical Data Link) aircraft terminal. We applied high-speed frequency hopping technology, cognitive radio technology, and receive filter bank technology to efficiently use limited frequency resources with radar and other communication equipment using the same frequency band. The high-power amplifier is physically composed of a transmitter, a receiver, a mechanical part, and a cable assembly, and is designed to meet temperature characteristics and electrical characteristics such as maximum transmission distance and reception sensitivity. Modeling and simulator were used to satisfy the requirement of high power amplifier. The transmit power and the noise figure were measured at 50.02dBm and 2.682dB, respectively. It was confirmed that all the required specifications were satisfied in the electrical characteristics test and the environmental characteristic test.

• Fire Science and Engineering
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• v.34 no.3
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• pp.35-42
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• 2020

The accurate prediction of fire detector activation time is required to ensure the reliability of fire modeling during the safety assessment of performance-based fire safety design. The main objective of this study is to determine the activation temperature and the response time index (RTI) of a fixed heat detector, which are the main input factors of a fixed-temperature heat detector applied to the fire dynamics simulator (FDS), a typical fire model. Therefore, a fire detector evaluator, which is a fire detector experimental apparatus, was applied, and 10 types of domestic fixed-temperature heat detectors were selected through a product recognition survey. It was found that there were significant differences in the activation temperature and RTI among the detectors. Additionally, the detector activation time of the FDS with the measured DB can be predicted more accurately. Finally, the DB of the activation temperature and RTI of the fixed-temperature heat detectors with reliability was provided.

• Information and Communications Magazine
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• v.31 no.12
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• pp.17-24
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• 2014

빅데이터, IoT, 클라우드 인프라 등 기술의 발달에 따라 일상생활 중에서도 개인과 환경의 변화에 대해 실시간 데이터 수집이 용이하게 되었다. 이를 활용하여 개인의 다양한 특성과 상황을 인지하고 다면적으로 의미를 분석할 수 있는 개인의 라이프스타일(lifestyle, 생활습관) 분석 기술이 중요하게 부각되고 있다. 이 라이프스타일 데이터는 개인의 질병이나 사회 심리적 문제의 원인 분석과 미래 트렌드의 변화예측을 할 수 있는 중요한 근거로 활용된다. 최근 이를 위한 연구로서 활동량, 스트레스, 위치, 수면 등의 라이프스타일 패턴을 추출하여 체계적인 프로세스로 삶의 질을 향상시키는 웰니스 (Wellness) 예측케어 서비스 연구와 서비스들이 활발히 진행되고 있다. 하지만 이러한 서비스를 제공하기에 앞서 개인의 복잡한 라이프스타일 패턴의 추출이 단편적으로만 이뤄지고 있어서, 패턴들 사이의 복잡한 관계를 분석하거나 연계 서비스로의 확장 및 라이프스타일 패턴의 재사용적인 측면에서의 문제가 어려운 이슈가 되고 있다. 이 때문에 웰니스 서비스의 신뢰도가 낮아 사용자가 단순히 재미로 느끼는 수준이거나 일회성에 그치는 모바일 어플리케이션 서비스를 제공받는 경우가 다반사이다. 본 논문에서는 IoT환경에서 다양한 스마트 디바이스에 의해 수집되는 라이프로그로 부터 라이프스타일 패턴 추출 및 모델링, 라이프스타일 패턴 분석으로부터 개인의 행동 추론 및 예측, 원인파악과 관련 지표를 정량적으로 설계하는 분석 엔진 개발 방안, 서비스 디자인을 통하여 실효적인 생활개선의 변화를 유도하는 기술, 개인의 심리적 특성까지 고려한 신뢰성 높은 케어 서비스 제공까지의 전반적인 웰니스 예측케어 서비스시스템 프로세스 및 플랫폼 설계 방안을 제시한다.

• School Mathematics
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• v.18 no.2
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• pp.349-373
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• 2016

Comparison of curriculum between various countries is a major research method for studying a course and content quoted on Korea's national curriculum. Therefore this research focuses on comparing and analyzing a new curriculum which Australia has announced on 2012 and conducting since 2015. From this research result, we found that Australia's curriculum achievement shows some unique characteristics. Such examples can be dealing a concept with real life context and proposing a mathematical content specifically. Also they introduce the definite integral by defining to the sum of series. There are other characteristics such as modelling motion, and numerical integration which Korea's highschool curriculum achievement doesn't deal with, and the content of vector calculus is handled more deeply. As a result of analyzing Australia's textbook, it fully deals with the supplementary notion to help understand mathematical definition. Hence further research will be needed later on to relieve the aspect of cognitive burden on Korean learners.