• Journal of Information Management
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• v.43 no.1
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• pp.89-108
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• 2012

Deeper understandings of school library-assisted instruction from teachers are required to develop students' self-directed learning skills which can improve their learning capabilities, problem solving techniques and learning attitudes. The objective of this study was to examine whether there is difference in subject teachers' perception of the necessity and effectiveness of the group type, class model, and collaborative class of class utilizing the school library and to apply and activate class utilizing the school library constructively in the field of education. For this purpose, this study inquired into the concept, necessity, type and process of class utilizing the school library, etc. and conducted a questionnaire survey of 278 subject teachers sampled from 30 high schools in 10 areas of Gyeonggido.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2145-2152
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• 2015

The existing CCTV has limitation such as problem on usage of the off-line type of recorded image for specific investigation, and requirement on interactive operator intervention for real-time surveillance. Therefore, it is required to develop the intelligent CCTV equipped with various functionalities in order to overcome drawbacks mentioned above. In this paper, implementation methods of image-based virtual fence were proposed by using the spline curves with supplied control for setup of surveillance area. In addition, pre-alarm region within the predefined distance was established with tangent and normal lines extracted from control points. The image-based virtual fence can be used for remote detection of intrusion and provision of real-time intrusion alarm, and can be expected to use in safety-related application areas including security and crime prevention.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1310-1320
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• 2020

Low-quality soil for land reuse is a crucial problem in vegetation quality and especially to waste disposal sites in mining areas. It is necessary to find suitable materials to improve the soil quality and especially to increase soil microbial diversity and activity. In this study, pot experiments were conducted to investigate the effect of a mixed material of humic acid, super absorbent polymer and biochar on low-quality soil indexes and the microbial community response. The indexes included soil physicochemical properties and the corresponding plant growth. The results showed that the mixed material could improve chemical properties and physical structure of soil by increasing the bulk density, porosity, macro aggregate, and promote the mineralization of nutrient elements in soil. The best performance was achieved by adding 3 g·kg^-1 super absorbent polymer, 3 g·kg^-1 humic acid, and 10 g·kg^-1 biochar to soil with plant total nitrogen, dry weight and height increased by 85.18%, 266.41% and 74.06%, respectively. Physicochemical properties caused changes in soil microbial diversity. Acidobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Firmicutes, Nitrospirae, Planctomycetes, and Proteobacteria were significantly positively correlated with most of the physical, chemical and plant indicators. Actinobacteria and Armatimonadetes were significantly negatively correlated with most measurement factors. Therefore, this study can contribute to improving the understanding of low-quality soil and how it affects soil microbial functions and sustainability.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.4
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• pp.385-394
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• 2006

The application areas of traditional push-pull converters are limited because the voltage stress of switches is high (twice of the input voltage). But the push - pull converter topology is suitable for unregulated low-voltage to high-voltage power conversion such as the fuel cell. This paper presents a novel power converter structure that is very suitable for the DC/DC converter in fuel cell systems. Based on this structure, a ZVS- ZCS push-pull converter is proposed. The switches of the proposed push-pull converter can operate under ZVS or ZCS condition with the help of a new passive clamping circuit. The passive clamping techniques solves the voltage overshoot problem. Because the buck converter circuit operates at twice the synchronous switching frequency of the push-pull converter, the peak current in the current-fed inductor and transformer is reduced. The operation principle of the proposed converter is analyzed and verified by simulations and experimental results. A 1 kW DC/DC converter was implemented with DSP TMS320F2812, from which experimental results have shown that efficiency improvement and surge suppression can be achieved effectively.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.1
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• pp.1-7
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• 2020

Directivity control technology of sound system is a key technology for improving sound quality. Providing a line source rather than a point source in an acoustic system can reduce the effects of attenuation interference at long distances, thereby providing high quality sound. In particular, A line-array speaker system can be used to provide coherent, high-quality sound over long distances. However, high frequencies have shorter wavelengths, so the distance between the speakers of a line array system must be shorter, but there are physical limitations. In this paper, we designed a wave guide and installed it in the speaker's compression driver to solve this problem. We measured and tested various acoustic characteristics to verify the performance of the speaker. As a result, when the line array sound system is constructed using the developed speakers, it is possible to provide a line source in all areas including the treble range, thereby achieving the same effect as a single extended source and providing high quality sound up to far distances.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.51-52
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• 2012

Safety at sea continues to be an important topic for research. The factors that contribute to safety issues are often complex and unclear. Lack of non-technical skills in such areas as communication, teamworking, situational awareness, decision making etc. are well documented as directly affecting safety in high risk work settings such as on board merchant vessels. Competence in non-technical skills can be affected by various habits and circumstances that influence a worker and result in either positive thinking and behaviour or negative thinking and behaviour. Negative thinking can cause stress, anger, frustration; loneliness etc. and this can possibly result in behaviour or actions that undermine the safety of crew and ship. Factors that may contribute to these negative thoughts and behaviours are many and varied and this paper will be looking at one aspect: mobile phone use. In the Republic of Korea, dependency on mobile phones is uniquely high. Maritime students are also susceptible to such dependency and this paper will demonstrate that the symptoms associated with mobile phone addiction and dependency, and in particular the symptoms of withdrawal, are important factors that need to be mitigated in order to improve safety at sea. Although the benefits of mobile phones are many it will be suggested that over-reliance, dependency or addiction can result in negative thinking or behaviour that may directly or indirectly contribute to the factors that cause incidents and accidents at sea. It will be suggested that the most appropriate method of dealing with this problem is twofold: firstly, through training at the educational level and secondly, by encouraging the shipping industry and government to invest more into providing seafarers with better access to the communication methods that they are used to on shore in order to improve work conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1344-1356
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• 2009

The DDS (Data Distribution Service) is a data-centric communication technology that provides an efficient communication service that supports a dynamic plug & play through an automatic setting of participants' location information for each data (Topic) by using DDS discovery technique. This paper proposes the hierarchical-structured DDS discovery technique (SPDP-TBF) suitable for the large-scale distributed systems by comparing and analyzing the existing DDS discovery techniques in terms of performance and problem areas. The proposed SPDP-TBF performs the periodic discovery of the involved participants only by having separate hierarchical managers which take charge of the registration and search (of participants) so that a participant sends its information to the related participants only, and it enhances the effectiveness of the message transfer. Moreover, the proposed SPDP-TBF provides the improved scalability by performing the hierarchical discovery through hierarchical manager nodes so that it can be applied to the large-scale distributed system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1321-1327
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• 2009

In this paper, as the mobile communication service is widely used and the demand for wireless repeaters is rapidly increasing because of the easiness of extending service areas. But a wireless repeater has a problem the oscillation due to feedback signal. We proposed a new hybrid interference canceller using the adaptive filter with CMA(Constant Modulus Algorithm)-Grouped LMS(Least Mean Square) algorithm in the adaptive interference canceller. The proposed interference canceller has better channel adaptive performance and a lower MSE(Mean Square Error) than conventional structure because it uses the cancellation method of Grouped LMS algorithm. The proposed detector uses the LMS algorithms with two different step size to reduce mean square error and to obtain fast convergence. This structure reduces the number of iterations for the same MSE performance and hardware complexity compared to conventional nonlinear interference canceller.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.2126-2133
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• 2009

As expected that a robot-industry will grow up rapidly toward a huge market, many countries try to develop the official policies to support a robot-industry. Following this trend, many robot researches are proceeded in the various technical areas by the government-initiated R&D strategies in Korea. These R&D programs are archived by academic-industrial collaboration and furthermore, include the disseminated linkage of academic-industrial collaboration and the human resource development program which pursues the problem solving and technical training for companies suffered by several technical difficulties. This paper shows the several analyses and considerations of provisional results of these collaboration programs. First, each program of specialized plan for next generation is reviewed and the accomplishment of human resource development for robot research is evaluated. Finally, several considerations are represented for continuous and desirable expansion of these programs.

• Journal of Information Science Theory and Practice
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• v.7 no.4
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• pp.56-64
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• 2019

Planting intercropping in rubber plantations is another alternative for generating more income for farmers. However, farmers still lack the knowledge of choosing plants. In addition, information for decision making comes from many sources and is knowledge accumulated by the expert. Therefore, this research aims to create a decision support system for growing rubber trees for individual farmers. It aims to get the highest income and the lowest cost by using semantic web technology so that farmers can access knowledge at all times and reduce the risk of growing crops, and also support the decision supporting system (DSS) to be more intelligent. The integrated intercropping ontology and rule are a part of the decision-making process for selecting plants that is suitable for individual rubber plots. A list of suitable plants is important for decision variables in the allocation of planting areas for each type of plant for multiple purposes. This article presents designing and developing the intercropping ontology for DSS which defines a class based on the principle of intercropping in rubber plantations. It is grouped according to the characteristics and condition of the area of the farmer as a concept of the rubber plantation. It consists of the age of rubber tree, spacing between rows of rubber trees, and water sources for use in agriculture and soil group, including slope, drainage, depth of soil, etc. The use of ontology for recommended plants suitable for individual farmers makes a contribution to the knowledge management field. Besides being useful in DSS by offering options with accuracy, it also reduces the complexity of the problem by reducing decision variables and condition variables in the multi-objective optimization model of DSS.