• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.200-207
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• 2017

The purpose in having a control surface on ships is to control the motion of the ship. The control surface may be composed entirely of a single movable surface or of a combination of fixed and movable portions. A control surface has one sole function to perform in meeting its purpose, and that is to develop a control force in consequence of its orientation and movement relative to the water. The forces and moments generated as a result of this rotation and angle of attack then determine the manoeuvring characteristics of the ship. In this paper, two-dimensional flow characteristics of a flapped rudder and a water-blowing control rudder were accomplished respectively by PIV method in a circulating water channel. Model test has been carried out with different angles of attack of main foil (NACA 0012) and flap's deflection angles to predict the performance of the flapped rudder and the water-blowing control rudder. The 2-frame particle tracking method has been used to obtain the velocity distribution in the flow field. $Re{\fallingdotseq}3.0{\times}10^4$ has been used during the whole experiments and measured results have been compared with each other.

• Informatization Policy
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• v.21 no.2
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• pp.24-48
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• 2014

Smart working, along with the spread of smart device use, has recently garnered increased interest. The issue has become focused on low labor productivity over working time, work-life balance and social discussion. There has also been a shift in working styles due to the development of mobile, security, and cloud computing-related IT technology support and activation of the smart work environment. However, former research show concern that smart working may not meet the initially expected levels of productivity. This empirical study was carried out to introduce the impact of teleworking on increased productivity and satisfaction in companies and public institutions through user interviews, a socio-technical systems approach and surveys. To summarize the results of this study, 'Telework satisfaction' is directly influenced by 'Work-life balance', 'Telework-system fit, and 'Telework-job fit'. Direct impact factors of 'Telework productivity'are 'Telework-job fit', 'Telework satisfaction', and 'Telework environment quality'.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.452-458
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• 2021

The value and importance of personal information are increasing due to the increasing number of fields where the Internet environment and computing environment are used, and user authentication technology is also changing. Until now, accredited certificates, which are mainly used in the financial sector, are being replaced with biometric authentication technology due to the problem of revocation. However, another problem is that biometric information cannot be modified once it is leaked. Recently, with the advent of blockchain technology, research on user authentication methods has actively progressed. In this paper, both public certificate and blockchain-based user authentication can be used without system change, and a new DID issuance and reissuance method that can replace the resident registration number is presented. The proposed system can be used without restrictions in a blockchain. However, the currently used DID requires installation of an application at the Interworking Support Center for verification. Since a DID can be authenticated without registering as a member, indiscriminate information collection can be prevented. Security, convenience, and determinism are compared with the existing system, and excellence is proven based on various attack methods, its portability, and proxy use.

• Korean Security Journal
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• no.55
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• pp.97-116
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• 2018

Due to the rapid developments of South Korea, local communities have faced various social pathologies which generated more violent crimes and criminalized younger students. Several horrendous violences, such as a Kangneung Girl assassination assault case in July 2017 and a Busan Girls assault case in September 2017, happened only between young students. This ignited a public uproar and people were more interested in related national policies and voiced for stronger penalties in ways that punish student offenders and abolish the juvenile law. In this respect, various effective policies are needed to prevent the school violence and to eliminate the students' fear of crime. These are expected to create an environment where students could enthusiastically study in a safe environment. Focusing on elementary school students, this study seeks to empirically analyse the effects of their perception of local crime control governance on their fear of crime and, subsequently, to suggest policy implications which could prevent future school violence and juvenile crimes and reduce the students' fear of crime. The results of this study are as follows: First, the analysis of the general fear of local crime control governance and the fear of crime showed that elementary school students' trust in police officers had a significant effect on the general fear. Second, the analysis of the local fear of crime control governance and the fear of crime highlighted that their trust in the police, social ties, intimacy between the police and residents had a significant effect on the specific fear. Therefore, this study is applicable in reality in that it can contribute to the prevention of school violence and reduction of fear of crime by constructing local crime control governance.

• Convergence Security Journal
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• v.21 no.1
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• pp.137-147
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• 2021

The purpose of this study is to summarize the variables for making the power expansion of terrorist organizations possible by analyzing the power transitions among the Somalia governments and terrorisms. For this, I created a framework after extracting the independent variables affecting the power transition using the theories of Hans J. Morgenthau, A.F.K Organski, K.J. Holsti. On the basis of these, I analyzed the power transitions among the organizations from August 2012(the foundation of Federal government) to August 2019. According to the results, the power area of the federal government is extremely narrowed, whereas the power areas of al-Shabaab, ISIS, and neutral conflict are largely expanded. The factors in the framework were embodied as the delay of powerful federal government foundation, the shortage of national military forces, the limitation of effective use of foreign forces, the continuation of cooperation and antagonism among armed terrorist organization, sanctuary environment of terrorists using the Sharia law, advantages of force recruitment resulted from the bad economic conditions, public support suitable for the Somalia environment. All of these factors work the causes of lasting anarchy condition of the federal government of Somalia by making the settlement of conflict against terrorist organizations.

• Journal of the Korean Regional Science Association
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• v.36 no.4
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• pp.3-23
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• 2020

This study aims to conceptualize the settlement inclusivity for overcoming social exclusion and the decline in quality of life of older people and to examine its effects on their mental health. The concept of the settlement inclusivity for older people focuses on the immediate environment around the place where they live. We proposed two domains for the conceptual framework; social domain that provides opportunities for community cohesion; spatial domain that provides security of residential area and access to basic services within walking distance. The social domain was represented by participation and interdependence, while the spatial domain by security and accessibility in the settlement inclusivity. Zero-inflated negative binomial regression model was constructed with 2017 National Survey of Older Koreans data to analyze the factors influencing depressive symptoms of older adults. The empirical results demonstrate that increased level of neighborhood network and social participation is associated with a decrease in the number of depressive symptoms. In addition, higher satisfaction in neighborhood environment and good accessibility to public transport/stores are associated with fewer depressive symptoms. Finally, housing condition and home ownership have a moderating effect on the relationship between social network/participation and depressive symptoms level, whereas they have no direct effects on depressive symptoms. This study demonstrates multi-dimensionally and mutually significant associations between settlement inclusivity and depressive symptoms for older people providing implications for urban planning and policies to improve mental well-being of older population.

• Design Convergence Study
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• v.16 no.3
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• pp.103-118
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• 2017

It is expected that the integrated control service of the public sector will be increased for the safety of citizens in the future. Therefore, In this study, we analyzed the classification of CCTV control center and the characteristics of interior design. The survey was conducted at eight control centers in Seoul that were constructed since 2007 and analyzed according to the criteria of general matters, services, spatial basic information, spatial structure, and internal structure. The results of the survey are summarized as follows. Based on the results of the study, the Integrated Control Center is a space where the ratio of the physical environment is not high but performs important tasks for the citizens of the city, which are operated 24 hours a day, and security and security. It is characterized by the efficient space allocation for the treatment, the design of the moving line, and the connection according to the urgent work flow. The results of this study are expected to be used as basic data for other integrated control center environment.

• Journal of Internet Computing and Services
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• v.21 no.1
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• pp.17-31
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• 2020

With the rapid development of block chain technology, attempts have been made to put the block chain technology into practical use in various fields such as finance and logistics, and also in the public sector where data integrity is very important. Defense Operations In addition, strengthening security and ensuring complete integrity of the command communication network is crucial for operational operation under the network-centered operational environment (NCOE). For this purpose, it is necessary to construct a command communication network applying the block chain network. However, the block chain technology up to now can not solve the security issues such as the 51% attack. In particular, the Practical Byzantine fault tolerance (PBFT) algorithm which is now widely used in blockchain, does not have a penalty factor for nodes that behave maliciously, and there is a problem of failure to make a consensus even if malicious nodes are more than 33% of all nodes. In this paper, we propose a Adaptive Consensus Bound PBFT (ACB-PBFT) algorithm that incorporates a penalty mechanism for anomalous behavior by combining the Trust model to improve the security of the PBFT, which is the main agreement algorithm of the blockchain.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.2 no.2 s.3
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• pp.31-42
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• 2003

Prepaid plastic card issued by Korea Highway Company had a lot of problems in end-user usage and management. HipassPLUS Card, which is a smart card used for a prepaid electronic payment, overcomes the problems of Prepaid Plastic card. HipassPLUS Card is also designed be compatible to other cards such as public transportation card. Thus, for the safety of using the card in such environment, the functionality and the security of HipassPLUS card should be faultless. This paper developed a test module including the test method, the test checklist, and the test procedure to examine the functionality and security of the payment mechanism of HipassPLUS card. The test module contains the method and the procedure to test the standard items according to the test checklist of HipassPLUS card. The test items and the test checklist of HirassPLUS card was selected under the provision of the specification of Korea Highway Company and ISO standard. The results of evaluation on HipassPLUS card using the proposed test module indicates that 4he HipassPLUS card satisfied the criteria under the characteristics of the functionality, security, and compatibility.

• Korean Security Journal
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• no.17
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• pp.337-360
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• 2008

Since the Cold war, many countries in the world have reduced the number of their military personnel. However, it is also factual that regional conflicts have been incessantly occurring around the world. In turn, specific governmental policies are also needed in certain countries. Recently, a resolution growingly accepted in the advanced countries is the outsourcing of the resources and services of private military companies, which benefits for governments to manage their military force efficaciously. The utilization of private military force, however, may potentially generate ethical and practical issues because of the non-specified international codes to regulate private military companies, the political misuse of private personnel without concerning the loss of public military employees in danger zones, the safety of private personnel in the field, and the possibility of genocide. Prior to accept a private military companies which may be adequate in the environment of the Korean military, it is necessary to review previous cases of foreign countries. In addition, it is also needed to determine the plausible boundaries of the operation of private military companies with taking into consideration of the situations of the Korean military and private business. Finally, the systemic governmental support is requested in order to foster the business of private military.