• 디지털융복합연구
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• 제19권3호
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• pp.127-135
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• 2021

본 연구에서는 사옥신축목적의 시설투자 공시기업을 대상으로 내부관계자의 거래행태에 따른 차별적 장기성과를 살펴봄으로써 자본시장의 정보비대칭 현상을 분석하고 있다. 이를 위해 한국거래소 유가증권과 코스닥시장에서 투자공시가 이루어진 기업을 대상으로 사건연구방법과 다중회귀분석을 활용하여 분석하였다. 연구결과 사옥신축 기업의 장기주가수익률은 평균적으로 양(+)의 유의한 값을 나타내고 있다. 공시 전후의 내부관계자 지분변화에 따라 차별적 장기성과가 나타나고 있으며, 회귀분석결과 내부관계자지분, 소액개인투자자의 지분변화는 각각 장기성과와 통계적으로 유의한 양(+)과 음(-)의 상관관계가 있음을 확인하였다. 이는 내부관계자가 경영자의 사적 의도에 대한 진위 여부 및 사옥신축이 기업에 미치는 영향을 판단할 수 있는 정보우위의 위치에 있음을 뒷받침해 줄 수 있는 연구결과로 풀이되며 지분변화요인이 사옥신축 기업에 대한 장기성과의 예측요인으로 활용될 수 있다는 측면에서 자본시장의 투자자들에게 실무적으로 유용한 정보를 제공해 줄 수 있을 것으로 기대된다.

• 디지털융복합연구
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• 제15권10호
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• pp.161-171
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• 2017

최근 리더십 연구에서 리더의 진정성이 중요한 이슈로 부각되고 있다. 리더십 발휘에 있어서 리더의 진정성 여부는 조직구성원들의 행동, 태도 및 성과에 큰 영향을 미치기 때문이다. 이에 본 연구는 진성리더십이 조직몰입, 조직시민행동 및 직무성과에 어떠한 효과가 있는지 살펴보고, 진성리더십의 효과성은 공공조직과 사조직에 모두 유효한지를 실증적으로 분석해 보고자 한다. 국내 다양한 조직에 종사하는 조직구성원들을 대상으로 설문을 실시하였으며, 회수된 설문지 444부(공공기업 243부, 민간기업 201부)가 분석에 사용되었고, 통계분석은 SPSS/WIN 23.0과 STATA 14.0 통계패키지를 사용하여 요인분석 및 회귀분석으로 검증하였다. 연구 결과를 요약하면, 진성리더십은 공공조직과 사조직에 대해 조직몰입, 조직시민행동, 직무성과 모두에 정(+)의 영향을 미치는 것으로 확인되었다. 요컨대, 진성리더십은 리더가 조직을 보다 효과적으로 이끌어 가는데 긍정적인 도움을 줄 수 있을 것으로 기대되고 이러한 관계는 공공조직이나 사조직에 모두 유의미한 효과를 가지는 것으로 보인다.

• Geomechanics and Engineering
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• 제31권2호
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• pp.129-147
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• 2022

The properties of soil are naturally highly variable and thus, to ensure proper safety and reliability, we need to test a large number of samples across the length and depth. In pile foundations, conducting field tests are highly expensive and the traditional empirical relations too have been proven to be poor in performance. The study proposes a state-of-art Particle Swarm Optimization (PSO) hybridized Artificial Neural Network (ANN), Extreme Learning Machine (ELM) and Adaptive Neuro Fuzzy Inference System (ANFIS); and comparative analysis of metaheuristic models (ANN-PSO, ELM-PSO, ANFIS-PSO) for prediction of bearing capacity of pile foundation trained and tested on dataset of nearly 300 dynamic pile tests from the literature. A novel ensemble model of three hybrid models is constructed to combine and enhance the predictions of the individual models effectively. The authenticity of the dataset is confirmed using descriptive statistics, correlation matrix and sensitivity analysis. Ram weight and diameter of pile are found to be most influential input parameter. The comparative analysis reveals that ANFIS-PSO is the best performing model in testing phase (R² = 0.85, RMSE = 0.01) while ELM-PSO performs best in training phase (R² = 0.88, RMSE = 0.08); while the ensemble provided overall best performance based on the rank score. The performance of ANN-PSO is least satisfactory compared to the other two models. The findings were confirmed using Taylor diagram, error matrix and uncertainty analysis. Based on the results ELM-PSO and ANFIS-PSO is proposed to be used for the prediction of bearing capacity of piles and ensemble learning method of joining the outputs of individual models should be encouraged. The study possesses the potential to assist geotechnical engineers in the design phase of civil engineering projects.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권10호
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• pp.2544-2560
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• 2013

As a cornerstone of the next generation air traffic management (ATM), automatic dependent surveillance-broadcast (ADS-B) system can provide continual broadcast of aircraft position, identity, velocity and other messages over unencrypted data links to generate a common situational awareness picture for ATM. However, since ADS-B messages are unauthenticated, it is easy to insert fake aircrafts into the system via spoofing or insertion of false messages. Unfortunately, the authentication for ADS-B messages has not yet been well studied. In this paper, we propose an efficient broadcast authentication scheme with batch verification for ADS-B messages which employs an identity-based signature (IBS). Security analysis indicates that our scheme can achieve integrity and authenticity of ADS-B messages, batch verification, and resilience to key leakage. Performance evaluation demonstrates that our scheme is computationally efficient for the typical avionics devices with limited resources, and it has low communication overhead well suitable for low-bandwidth ADS-B data link.

• 영어어문교육
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• 제11권1호
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• pp.17-36
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• 2005

The purpose of this study is to examine the ways in which CALL apply to enhance the motivational aspects of second language learning. Theories relevant to social, cognitive, and affective foundations of motivation are first reviewed to demonstrate the important role of motivational influences in improving learners' affect and achievements. Then, implications arising from such theories in strengthening the motivational aspects of CALL are explicated in the second part. With the spread of computer technology in language classrooms, the innovative role of CALL in the development and maintenance of intrinsic motivation can be illustrated. Specifically, CALL may provide cognitively supportive instruction geared towards improving students' performance. Also, it has been reported from the affective perspective that CALL can captivate learners' attention, promote their feelings and expectations of success, improve perceptions of control, and increase positive attributions to effort and ability. Finally, from a social learning perspective, CALL may enhance learners' self-efficacy and foster their achievement and positive affect through social interactions, proximal goal-setting, and attributional feedback. In the framework of CALL, students seem to be benefited by the immediacy and authenticity of contact with target languages and cultures made at their choices and decisions.

• 영어어문교육
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• 제11권4호
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• pp.365-389
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• 2005

The purpose of this study is to present the task model that is the most effective in English language methodology based on the investigation of task-based performance in Korean EFL classroom practice. The subjects were 538 high school students and 126 high school teachers, each of whom had common experiences using the materials of task-based activities for more than one year. To analyze the data, the program SPSS WIN 11.0 including frequency distribution and chi-square analysis was used. The results of the questionnaire analysis showed that both teachers and students had a comparatively high level of satisfaction in task rationale, but that they had some mixed responses in the fields of input data, settings, and activity types. To conclude, a few suggestions are made to provide some meaningful considerations for the EFL teachers and material developers: a) task goals and rationale that encourage the learner's positive motivation; b) authenticity of input data based on the real-world context; c) collaborative learning environment that enhances communicative interaction; d) proportional representation of the creative problem-solving activities related to discussions and decision-making processes; e) systematic introduction of integrated language skills. It also suggests that the multi-lateral task model, which has some positive assets compared to previous task models, be newly introduced and applied to the second language learning classrooms.

• Journal of Information Processing Systems
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• 제13권2호
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• pp.385-399
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• 2017

Nowadays, with the development of signal processing technique, the protection to the integrity and authenticity of images has become a topic of great concern. A blind image authentication technology with high tamper detection accuracy for different common attacks is urgently needed. In this paper, an improved fragile watermarking method based on local binary pattern (LBP) is presented for blind tamper location in images. In this method, a binary watermark is generated by LBP operator which is often utilized in face identification and texture analysis. In order to guarantee the safety of the proposed algorithm, Arnold transform and logistic map are used to scramble the authentication watermark. Then, the least significant bits (LSBs) of original pixels are substituted by the encrypted watermark. Since the authentication data is constructed from the image itself, no original image is needed in tamper detection. The LBP map of watermarked image is compared to the extracted authentication data to determine whether it is tampered or not. In comparison with other state-of-the-art schemes, various experiments prove that the proposed algorithm achieves better performance in forgery detection and location for baleful attacks.

• 한국병원경영학회지
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• 제17권4호
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• pp.167-187
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• 2012

Organizational growth is achieved through the process of finding opportunities in the environment and establishing a business model with internal and external resources. Bestian Hospital, which primarily focuses on saving the lives of patients with severe burns, has enlarged its business domain through deep understanding of burn patients' problems, including pain and complications during treatments, long-term treatments, skin reconstruction, and so on. Now Bestian is accelerating research for development of antipyretics and cosmetics for burn patients. The success of Bestian has been due to utilization of human and material resources that are essential to performance in the medical field. Also, Bestian properly used a management service organization(MSO) model and constructed an information technology(IT) system for supporting its businesses. However, previous successes do not guarantee continued success. Bestian is entering a new domain with different challenges than it has experienced so far, and how it deals with these challenges will decide its future.

• 한국컴퓨터정보학회논문지
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• 제17권12호
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• pp.159-167
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• 2012

공개키 기반(public key infrastructure)의 인증체계는 서비스 제공자와 사용자 모두에게 인증성과 보안성, 접근성, 경제성, 편의성을 제공으로 국내의 공공 및 민간 기업들은 웹 서비스의 인증방안으로 널리 사용되고 있다. 그러나 공개키 기반의 인증체계의 사용에 따른 여러 보안 취약 요인들이 나타나면서, 클라이언트 시스템의 안전성은 위협을 받고 있다. 따라서 본 논문은 공개키를 기반으로 하는 인증체계에 따른 취약 요인들을 사례연구 및 실험을 통해 분석함으로써, 향후 새로운 인증체계의 구축 및 성능향상을 위한 자료로 활용될 것으로 기대한다.

• Journal of Information Processing Systems
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• 제14권1호
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• pp.239-251
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• 2018

In existing cloud services, information security and privacy concerns have been worried, and have become one of the major factors that hinder the popularization and promotion of cloud computing. As the cloud computing infrastructure, the security of virtual machine systems is very important. This paper presents an immune-inspired intrusion detection model in virtual machines of cloud computing environment, denoted I-VMIDS, to ensure the safety of user-level applications in client virtual machines. The model extracts system call sequences of programs, abstracts them into antigens, fuses environmental information of client virtual machines into danger signals, and implements intrusion detection by immune mechanisms. The model is capable of detecting attacks on processes which are statically tampered, and is able to detect attacks on processes which are dynamically running. Therefore, the model supports high real time. During the detection process, the model introduces information monitoring mechanism to supervise intrusion detection program, which ensures the authenticity of the test data. Experimental results show that the model does not bring much spending to the virtual machine system, and achieves good detection performance. It is feasible to apply I-VMIDS to the cloud computing platform.