• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.28-37
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• 1996

Benzidine, an aromatic amine used primarily in the manufacture of azo dyes, is recognized as a urinary bladder carcinogen in humans. In rats, mice, and hamsters, chronic exposure to benzidine resulted in tumors of the liver. The present study was undertaken to suggest analyzing the metabolites of benzidine with the optimal condition, identify the metabolites of benzidine, and observe time variance of the metabolites in the isolated perfusated rat liver. N-acetylbenzidine was synthesized by acetylation of benzidine with acetic anhydride and separated by thin layer chromatography(TLC) and high performance liquid chromatography(HPLC). To analysis benzidine and the metabolites of benzidine, HPLC operating condition has been optimized by means of preliminary experiment. The mobile phase consisted of acetonitrile(37%) in phosphate buffer, flow rate maintained at 1.0 ml/min. Optimal detective conditions were electrochemicaldetector(ECD) at 0.75 V for benzidine and N-acetylbenzidine and ultravioletdetector(UVD) at 287 nm for N,N'-diacetylbenzidine. The separation system was composed of a guard column and a separation column(Polymer C18, $4.6{\times}250cm$) at a temparature of $40^{\circ}C$. The perfusion system was equilibrated for 30 minutes before addition of benzidine to the perfusate. Samples of the perfusate were collected at time intervals(0, 10, 20, 30, 60, 90, 120 min) during the 2 hour perfusion. Before analyzing samples by HPLC/ECD/UVD, samples had been treated with sep-pak. Samples of perfusate analyzed by HPLC/ECD/UVD and the metabolites of benzidine in the isolated perfused rat liver were N-acetylbenzidine and N,N'-diacetylbenzidine. Benzidine metabolized over 60% during the initial 30 minutes of perfusion, extensively by 1 hour, and was undetectable in the perfusate. N-acetylbenzidine increased by 30 minutes of perfusion, declined. N,N'-diacetylbenzidine increased the 0-90 minutes period, remained constant during the 90-120 minutes period.

• Journal of Korean Society of Transportation
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• v.33 no.2
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• pp.182-191
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• 2015

The Korean government introduced an automated speed enforcement system (ASES), which uses traffic enforcement cameras, to counteract safety issues that are caused by speeding. As the information of the traffic enforcement camera locations is provided to the drivers via navigation systems and mobile applications in a timely manner, drivers can avoid enforcement by momentarily diminishing their speeds only near the camera locations. To prevent drivers' evasional behavior and improve the effectiveness of ASES, section control, which enforces speeding vehicles by measuring their average travel speeds over a stretch of road and checking against the speed limit, has been recently implemented. In this study, Section Speed Enforcement Zone and Comparison Zone are compared in terms of traffic stream characteristics under free flow conditions. To this end, loop detector data were obtained from the three study sites and analyzed. The study results demonstrated that drivers maintain their speeds below the speed limit over the enforcement section with a lower variance of speeds.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.177-183
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• 2006

IMO and ITU-R have done an intensive study to develop performance standards and technical standards of maritime digital communication systems, respectively. In particular, each administration strives to develop new agenda items of adopting digital new technologies. IMO COMSAR submitted draft performance standard of LRIT to IMO MSC, so that IMO mandates carriage requirement of LRIT In addition to that, COMSAR is preparing performance standard of AIS-SART, and approved the utilization of mobile phones for SAR activities. On the other hand, a new agenda item concerning E-navigation strategy was submitted to MSC 81th meeting. These challenges toward enhanced maritime radio communication systems would make it change largely the concepts of traditional navigation We suggest future directions of maritime information communication systems, investigating the study results of IMO and ITU-R.

• Journal of Korean Library and Information Science Society
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• v.51 no.2
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• pp.355-379
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• 2020

Digital Library System(DLS) for the school library is a key access tool for school library materials. The purpose of this study was to find ways to improve the accessibility of materials through analysis of students' information search behavior in DLS. Data were collected through recording of 42 participants' DLS search process, and questionnaire. As a result, the search success rate and search satisfaction were found to be lower when the main purpose of DLS is simple leisure reading, information needs are relatively ambiguous, and when user experiences the complicated situations in the search process. The satisfaction level of search time sufficiency was the highest, and the search result satisfaction was the lowest. Besides, there was a need to improve DLS, such as integrated search of other library collection information, the recommendation of related materials, the print output of collection location, voice recognition through mobile apps, and automatic correction of search errors. Through this, the following can be suggested. First, DLS should complement the function of providing career information by reflecting the demand of education consumers. Second, improvements to DLS functionality to the general information retrieval system level must be made. Third, an infrastructure must be established for close cooperation between school library field personnel and DLS management authorities.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.102-109
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• 2009

What Michel Foucault has interpreted about Jeremy Bentham' Panopticon in the point of power relationship of ones's gaze is put in comparison with the characteristics shown in the modern media and mutual meanings are interpreted in the respect of a power relationship of modern gaze. Modern people communicating through media are placed in certain type of power relationship. This study analyzed the difference of it in the respect of the power of gaze in Panopticon and the consumption of information. Panopticon assumes single-network supervision, that is, one-way gaze. However, in modern media, interactive communication is possible based upon the development of information telecommunication technology. Therefore, this study aims to compare and study modern single-network supervision and multi-networks supervision based on information telecommunication technology. The development of various media such as internet, mobile phone and smart card has changed the single-network supervision system structured since modern times into the multi-network supervision system. 'Gaze-power' presented in the relationship to media enables us to discuss the problem of mutual receptiveness, the presence of various powers according to information structure and consumption power. In particular, the form provided by modern media has the complexity of mutual communication in the relationship of multi-networks, rather not assuming only one-way nature of single-network. Therefore, the approach of communication issue provided by modern media in the respect of multi-networks relationship was done by the power relationship of gaze in the respect of information communication. Gaze determines the power of watching. In addition, the visualization format aims at the power.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.4
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• pp.383-391
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• 2010

A Lifelog management system provides users with services to store, manage, and search their life logs. This paper proposes a fully-automatic collecting method of real world social contacts and lifelog search engine using collected social contact information as keyword. Wireless short-distance network devices in mobile phones are used to detect social contacts of their users. Human-Bluetooth relationship matrix is built based on the frequency of a human-being and a Bluetooth device being observed at the same time. Results show that with 20% of social contact information out of full social contact information of the observation times used for calculation, 90% of human-Bluetooth relationship can be correctly acquired. A lifelog search-engine that takes human names as keyword is suggested which compares two vectors, a row of Human-Bluetooth matrix and a vector of Bluetooth list scanned while a lifelog was created, using vector information retrieval model. This search engine returns more lifelog than existing text-matching search engine and ranks the result unlike existing search-engine.

• Journal of Korean Library and Information Science Society
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• v.15
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• pp.25-77
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• 1988

A Library is the fundamental character of culture in a country and it is also a barometer of culture in its community. Every cultural reality, however, can hardly come to fruition in a short time and so, it will be effected through a long time and tradition. This study aims at catching up how the above-mentioned public libraries have an influence on culture of its community people. For this purpose, the actual conditions of the public libraries have been investigated and analyzed and as a result of it, the problems have been reilluminated from the nation-wide point of view. And in the new changes, developing improvement measures have been tried to find. How to study was on the basis of the actual materials of the on the-spot survey, the interviews with the working officials and the response by way of questionnaire. Summing up the investigated and analyzed contents are as followings. In the above mentioned province, therefore, number of the public libraries are very limited compared with number of the people. And so, it is very essential to increase the public libraries in the province. In terms of the actual conditions, the public libraries lags far behind the other provinces in Korea from this library field. The present chronic conditions are the budgetary deficit, the collections insufficient to the legal minimal standards, the lack of professional librarians ignorance of the people and library managements by unprofessionals, etc.. This hinders the progress of the public libraries and to seculate them from the people. The improvements and the solutions to the above-mentioned problems are as follows. 1. To recruit the personnel sufficient to the legal standards and to reorganize the offices and to turn upward the highest class of librarian's position above the 4th class. 2. To secure collections sufficient to the legal standards and to strang then the extension services. 3. To organize the council composed of the chief librarians of the public libraries including the working chiefs in the province and to develop the works-in-hand of the libraries from the level of decision-making. 4. To organize the librarian training group and to study the working problems and to seek the qualified improvement of librarians. 5. The management of the public libraries in the province are, at present, der the Ministry of Education and the local government takes the financial power. So both should be shortly unified. 6. To do regularly the course of how to use library materials for the community people and to seek the inducement measures for the people through the various cultural events. 7. The public libraries organize the mutual cooperation networks and to seek the system automatized plans of free use of library materials and every library works. 8. To enlarge book mobile system actively and to infiltrate into the daily living of people deeply. Finally, what the present writer would like to speak to the chief librarians of the public libraries the human aspects of librarians should not be ignored no mater how excellent a library organization may be. In addition to this, the present writter is sure that the far-reached future of our library organization will depend on the librarians.

• Journal of Digital Contents Society
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• v.19 no.3
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• pp.505-512
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• 2018

Internet demand has increased rapidly, and Internet Protocol Version 4, the main Internet protocol, can not cope with various types of network demand in the future. Therefore, it is urgent to spread IPv6-based stable network to solve the shortage of Internet address resources. Due to the proliferation of IoT and the increase in mobile devices, efficient and optimal IPv6 routing design is indispensable. In this paper, we have studied about characteristics of IPv6, address system of IPv6, structure analysis and efficient routing technology among IPv6 terminals. Furthermore, experimental results on routing packet analysis and convergence time are presented in network - based IPv6 routing implementation environment. In addition, we show the results of the experiment analysis by dividing the implementation of IPv6 routing, operation test, and fail over performance into three kinds of routing protocol methods. As a result, this study can be applied to the introduction of IPv6 system, test bed environment construction, and network design.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.835-842
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• 2009

DVB-SSP is a new broadcasting system for hybrid satellite communications, which supports mobile handheld systems and fixed terrestrial systems. However, a critical factor must be considered in upper layer decoding which including erasure Reed-Solomon error correction combined with cyclic redundancy check. If there is only one bit error in an IP packet, the entire IP packet is considered as unreliable bytes, even if it contains correct bytes. IF, for example, there is one real byte error, in an If packet of 512 bytes, 511 correct bytes are erased from the frame. Therefore, this paper proposed two kinds of upper layer decoding methods; LLR-based decoding and hybrid decoding. By means of simulation we show that the performance of the proposed decoding algorithm is superior to that of the conventional one.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.32-39
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• 2006

5.8GHz DSRC(Dedicated Short Range Communications) is a short to medium range communications service that supports both public safety and private operations in roadside to vehicle and vehicle communication. However the 5.8GHz frequency may cause the shadowing effect or communication blocking problem when there is an obstacle or another vehicle between RSE (Road Side Equipment) and OBE (On Board Equipment). In this paper, to solve this problem of the 5.8GHz DSRC, we propose a relay protocol based on the standard of DSRC radio communication between RSE and OBE in the 5.8GHz band made by TTA (Telecommunication Technology Association). By using the proposed relay protocol to DSRC system and intervehicle communication, we also consider a fixed relay protocol and mobile relay protocol. We expect to apply this relay protocol for the DSRC intervehicle communication and video communication between drivers and safe distance among vehicles in the near future.