• Journal of Information Management
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• v.21 no.2
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• pp.9-23
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• 1990

CD-ROM technique, not more than 10 years after development, goes through rapid growth, has been taken advantage of several practical application parts. Needless to say about bibliographic data, numeric value, the phonetics, an image and a picture data that are recorded as abstract or full text, and offered and applied to industry, information service including library, it can be used for library staffs, information retrieval. Escape from the need of one disc drive and one computer to access one disc, now we organize an ideal system that can be retrieved several CD-ROM used only one drive, several users can access several information, so networking is possible through LAN. In this article, we studied the function and type, characteristics, system, structure, data block, production procedure, standardization of CD-ROM LAN.

• Tribology and Lubricants
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• v.31 no.4
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• pp.157-162
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• 2015

In this study, an ultrasonic nanocrystalline surface modification (UNSM) technique is applied to tungsten carbide-cobalt (WC-Co) to extend the service life of carbide parts used in press mold. The UNSM technique modifies the structure, reduces the surface roughness, increases the surface hardness, induces the compressive residual stress, and increases the wear resistance of materials by introducing severe plastic deformation. The surface roughness, hardness, and compressive residual stress of WC after UNSM treatment improve by about 42, 10, and 71%, respectively. A wear test under dry conditions is used to assess the effectiveness of the UNSM technique on the friction and wear behavior of WC. The UNSM technique is found to reduce the WC friction coefficient by approximately 21% and enhance the wear resistance by approximately 85%. The improved friction and wear behavior of WC may be mainly attributed to the increased hardness and compressive residual stress. Moreover, the WC specimen is treated by UNSM technique using three different WC, silicon nitride (Si₃N₄) and stainless steel (STS304) balls. The surface treated by WC balls shows the highest hardness when compared with treatment by stainless steel and silicon nitride balls. According to the obtained results, the UNSM technique is believed to increase the durability of the carbide component by improving the friction and wear behavior.

• Journal of the Korean Regional Science Association
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• v.12 no.2
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• pp.99-116
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• 1996

This study investigates the nature and patterns of interrelation between the emerging information and communication technology(ICT) and the organization of corporate space, both theoretically and empirically. In this work, ICT is conceptualized not so much a space-adjusting technology as an organizational technology. ICT is considered as a governance technology which is related to coordination function within a firm. Therefore, it is supposed to have a great relevance to the spatial reorganization of functions within a firm. Both questionnaire and case study method are used to gather necessary data from Korean electronics manufactures. The results of this study can be summarized as follow. First, the spatial structure of a firm, which is operationalised as the number and type of spatially separated establishments, is turned out to have a great explanatory power to its adoption of computer networks. Computer networks in muli-locational companies are introduced to overcome the limits of its spatial structure, such as duplication of functions, such as duplication of functions, loss of time spent in proceeding a job between different functional units, and unresponsiveness to the change of market demand. Second, new spatial division of labor and function could be possible through a series of business process reengineering, not through the mere adoption of ICT. Case studies reveal that computer network could help a firm to realize new forms of spatial division of labor, especially in those functions which is mainly based on the flow of information. Such function as ICT management, sales logistics and after-sales service are major parts where a new operational unit has appeared with the help of ICT. From above results, it can be concluded that the interrelations between ICT and organizational space should be approached intimately integrated with the change of industrial structure and it's organizational implications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.8
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• pp.4077-4091
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• 2017

This paper presents the design of a broadcasting scenario and system for an 8K-resolution content. Due to an 8K content is four times larger than the 4K content in terms of size, many technologies such as content acquisition, video coding, and transmission are required to deal with it. Therefore, high-quality video and audio for 8K (ultra-high definition television) service is not possible to be transmitted only using the current terrestrial broadcasting system. The proposed broadcasting system divides the 8K content into four 4K contents by area, and each area is hierarchically encoded by Scalable High-efficiency Video Coding (SHVC) into three layers: L0, L1, and L2. Every part of the 8K video content divided into areas and hierarchy is independently treated. These parts are transmitted over heterogeneous networks such as digital broadcasting and broadband networks after going through several processes of generating signal messages, encapsulation, and packetization based on MPEG media transport. We propose three methods of generating streams at the sending entity to merge the divided streams into the original content at the receiving entity. First, we design the composition information, which defines the presentation structure for displays. Second, a descriptor for content synchronization is included in the signal message. Finally, we define the rules for generating "packet_id" among the packet header fields and design the transmission scheduler to acquire the divided streams quickly. We implement the 8K broadcasting system by adapting the proposed methods and show that the 8K-resolution contents are stably received and serviced with a low delay.

• Korea Trade Review
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• v.46 no.2
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• pp.19-38
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• 2021

This study aims to analyze the foreign asset leverage effect on Korean oil & gas companies' foreign profits and to maintain the appropriate foreign asset volume for reducing exchange risk. For a long time, large Korean companies, including oil companies, overheld foreign currency liabilities. For this reason, most large companies have been burdened to hedge exchange risk and this excess limit holding deteriorated total profit and reduced foreign currency asset management efficiency. Our paper proceeds in presenting a three-stage analysis considering diversified exchange risk factors through estimation on transformation of foreign transactions a/c including annual trends of foreign asset and industry specifics. We also supplement incomplete the estimation method through a practical hedging case investigation. Our research parts are differentiated on the analyzing four periods considering period-specifics The FER value of the oil firms ranged from -0.3 to +2.3 over the entire period. The results of the FER Value are volatile and irregular; those results do not represent the industry standard comparative index. The Korean oil firms are over the credit limit without accurate prediction and finance high interest rate funds from foreign-owned banks on the basis on a biased relationship. Since the IMF crisis, liabilities of global firms have decreased. Above all, oil firms need to finance a minimum limit without opportunity losses on the demand forecast and prepare for uncertainty in the market. To reduce exchange risk from the over-the-limit position, we must consider factors that affect the corporate exchange risk on the entire business process, including the contract phase.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.998-1019
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• 2024

Mobile cloud computing is a very attractive service paradigm that outsources users' data computing and storage from mobile devices to cloud data centers. To protect data privacy, users often encrypt their data to ensure data sharing securely before data outsourcing. However, the bilinear and power operations involved in the encryption and decryption computation make it impossible for mobile devices with weak computational power and network transmission capability to correctly obtain decryption results. To this end, this paper proposes an outsourcing decryption algorithm of verifiable transformed ciphertext. First, the algorithm uses the key blinding technique to divide the user's private key into two parts, i.e., the authorization key and the decryption secret key. Then, the cloud data center performs the outsourcing decryption operation of the encrypted data to achieve partial decryption of the encrypted data after obtaining the authorization key and the user's outsourced decryption request. The verifiable random function is used to prevent the semi-trusted cloud data center from not performing the outsourcing decryption operation as required so that the verifiability of the outsourcing decryption is satisfied. Finally, the algorithm uses the authorization period to control the final decryption of the authorized user. Theoretical and experimental analyses show that the proposed algorithm reduces the computational overhead of ciphertext decryption while ensuring the verifiability of outsourcing decryption.

• Korean Journal of Medicinal Crop Science
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• v.10 no.5
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• pp.379-383
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• 2002

The significant chemical components estimating the quality and growth characteristics in different parts of tea plants were compared and analyzed in the shoots of shading tea plants. The results are summarized as follows. The leaves length, leaves width and weigth of 100 buds in the leaves were increased with growing, while the leaf moisture was decreased. The contents of total nitrogen, caffeine, vitamin C and saponin in the leaves were decreased with growing, while those of total amino acid and chlorophyll were the highest in the 4th leaves and in 3rd leaves, respectively. The content of tannin ranged from 9.53% to 11.23%. The content of tannin at the 1st leaves was the highest as 11.24%, but that of the 4th leaves was the lowest as 9.53%. the content of fatty acid at the 2nd leaves was the highest as 3,594mg/100g, and that of the 5th leaves was the lowest as 2,782mg/100g. The contents of palmitic acid and stearic acid were the highest in the 5th leaves, but those of oleic acid, linoleic acid and linolenic acid were the highest at the 2nd leaves. In conclusion, the 5th leaves among tea shoots plucked after shading for 15 days could be used to manufacture powder green tea.

• Journal of the Korean earth science society
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• v.28 no.1
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• pp.14-23
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• 2007

The purpose of this study was to investigate beginning earth science teachers' perceptions about Learning in Geologic Field Trip. The hundred and sixteen high school earth science teachers who were in the training for their promotion answered the questionnaire of Learning in Geologic Field Trip. It was divided into five parts: needs and educational values, teachers' experiences and their difficulties, and desirable teaching methods of Learning in Geologic Field Trip. Results indicated that the participants perceived Learning in Geologic Field Trip important in earth science education and responded positively to the educational values of Learning in Geologic Field Trip. Most of the beginning teachers had experience of geologic field trip, but did not learn how to teach it to their students during the geologic field trip in the pre-service training program. It was shown that only a few teachers had experience of geologic field trip and of teaching students in the outdoor of geologic fields after they became a classroom teacher. Most of the participants perceived that teaching students about the geologic field trip is difficult because of lack of their experience. In order to overcome the difficulty, teachers suggested that they need to learn how to teach the geologic field trip to students through their in-service training. leachers suggested that a desirable teaching method of the geologic field trip is to provide teachers with a teacher's manual including geological explanation and information about field trip sites before their visit so that they can scaffold it and facilitate the students' cooperative group activity during the field trip. As a follow up activity, the participants agreed that the presentation and discussion about the results should concur.

• Industry Promotion Research
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• v.8 no.2
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• pp.157-164
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• 2023

Since there are no related laws and regulations in the Korean private investigation industry, anyone can freely operate it if they report the business to the tax office. The reality is that companies hire PI to investigate rival companies and employees for specific reasons, as they generally rely on individual requests. The Korean PI industry is divided into two parts. The first are retired police officers and investigators who have experience in criminal investigation. The second are private citizen who can conduct investigation service activities runs a PI agency after everyone has registered with the tax office. It is no exaggeration to say that the current legal conflicts and legal problems that arise in the PI service cannot be ruled out because civilians are relatively less knowledgeable than PIs and legal experts. Therefore, in order for PI industry to operate stably in Korea, we will first study the concept and type of PI industry, comparative analysis of past PI laws, current status and reality of PI industry, and study the current status and references.

• Journal of Preventive Medicine and Public Health
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• v.28 no.4 s.51
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• pp.809-844
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• 1995

The purposes of this study are to define the scope of occupational health management and to classify occupational management by review of related journals from 1945 to 1994 in Korea. The steps of this study were as follows: (1) Search of secondary reference; (2) Collection and review of primary reference; (3) Survey; and (4) Analysis and discussion. The results were as follows ; 1. Most of the respondents majored in occupational health(71.6%), and were working in university (68.3%), males and over the age 40. Seventy percent of the respondents agreed with the idea that classification of occupational health management is necessary, and 10% disagreed. 2. After integration of the idea of respondents, we reclassified the scope of occupational health management. It was defined 3 parts, that is , occupational health system, occupational health service and others (such as assessment, epidemiology, cost-effectiveness analysis and so on). 3. The number of journals on occupational health management was 510. It was sightly increased from 1986 and abruptly increased after 1991. The kinds of journals related to occupational health management were The Korean Journal of Occupational Medicine(18.2%), Several Kinds of Medical Colloge Journal(17.0%), The Korean Journal Occupational Health(15.1%), The Korean Journal of Preventive Medicine(15.1%) and others(34.6%). As for the contents, the number of journals on occupational health management systems was 33(6.5%) and occupational health services 477(93.5%). Of the journals on occupational health management systems, the number of journals on the occupational health resource system was 15(45.5%), occupational finance system 8(24.2%), occupational health management system 6(18.2%), occupational organization 3(9.1%) and occupational health delivery system 1 (3.0%). Of the journals on occupational health services, the number of journals on disease management was 269(57.2%), health management 116(24.7%), working environmental management 85(18.1%). As for the subjects, the number of journals on general workers was 185(71.1%), followed by women worker, white coiler workers and so on. 4. Respondents made occupational health service(such as health management, working environmental management and health education) the first priority of occupational health management. Tied for the second are quality analysis(such as education, training and job contents of occupational health manager) and occupational health systems(such as the recommendation of systems of occupational and general disease and occupational health organization). 5. Thirty seven respondents suggested 48 ideas about the future research of occupational health management. The results were as follows: (1) Study of occupational health service 40.5%; (2) Study of organization system 27.1%; (3) Study of occupational health system (e.g. information network) 8.3%; (4) Study of working condition 6.2%; and (5) Study of occupational health service analysis 4.2%.