• Journal of Wetlands Research
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• v.6 no.4
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• pp.59-69
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• 2004

Constructed wetlands are regarded as an important water treatment system for agricultural water quality improvement and management. The purpose of this study is to evaluate the application of subsurface flow wetland(SFW), using the Pharagmites australis as macrophytes, and to clarify the basic and essential factors to be considered in the construction and management of constructed wetlands. This study was carried out relatively short hydraulic residence time(HRT), 6hr ~ 72hr (3days), using eutrophic reservoir water with relatively low concentrations of influent and large quantity to be treated. The effluent satisfied the criteria of agricultural water quality. Removal efficiencies of Biochemical oxygen demand(BOD), Chemical oxygen demand(COD), Suspended solids(SS) and Chlorophyll a(Chl-a) were high in HRT 24hr, not any more significant increasement of removal efficiencies in HRT 48hr and 72hr. However, removal efficiencies of nitrogen and phosphorus increased as HRT increased, showing the highest efficiency at the 72hr of HRT in nitrogen, and 48hr in phosphorous. The SFW was very effective system for reservoir water quality improvement, and had the advantages of the reduction of purchasing cost to land required, lack of odors, and harmful insects, especially mosquito, the improvement of the scenic beauty and minimal risk of public exposure. Therefore, it was evaluated that the SFW was very available water treatment system for the water quality improvement of agricultural reservoir. However, it was need to consider with application of the SFW in high cost of construction and troublesome of management.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.2
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• pp.177-182
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• 2004

This experiment was conducted to compare the agronomic characteristics and productivity inintroduced vetch cultivar at the experimental field of Grassland and Forage Crops Division, National Livestock Research Institute from 1999 to 2000. The experiment was arranged in a randomized block design with three replications. The vetch cultivar used in this study were 8 cultivar(Haymaker plus, Common, Capello, Namoi, Victa, Aneto, Popany, Korean milk vetch). Namoi, Victa and Aneto cultivar were died during winter. The cultivar having the fastest flowering date was Korean milk vetch while the flowering date of Common was the latest as 22th May. The average dry matter(DM) content was 14.7% and crude protein(CP) content was 20.9%. Common showed the highest CP content by 23.1% and Korean milk vetch showed the lowest content by 18.0%. Average acid detergent fiber(ADF) and neutral detergent fiber(NDF) content were 33.5 and 42.5% respectively. All cultivar showed the first grade of RFV(relative feed value). The productivity of vetch cultivar were severely different according to the winter hardness. Common showed the highest DM yield by 8,664kg/ha, but the DM yield of Capello and Popany were low by 3,004 and 2,114kg/ha, respectively. The yield of CP and TDN(total digestible nutrient) also was high at Common. The results of this experiments indicated that the productivity of vetch cultivar was effected greatly depending on winter hardness, therefore it was thought winter hardness is the main factor for introducing vetch cultivar.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6C
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• pp.614-622
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• 2006

In this paper, we propose an efficient packetization method to reduce the packetization overhead. For the purpose, we firstly verify the relationship between packet length and packet loss rate. The empirical results show that as the packet length is larger than the path MTU, the packet loss rate is drastically increased, producing poor visual quality at the receiver side. However, as the length of the packet is reduced, we should transmit more packets per frame and the packetization overhead will be increased. This increase in the packetization overhead reduces the number of bits allocated to the video data, resulting in the low visual quality. Therefore, each packet should be packetized to have the packet length close to the path MTU. In this paper, we show that the this process of the packetization with the constraint on the packet length is very similar to the dynamic storage allocation in the operating system. We had thoroughly surveyed the dynamic storage allocation methods used in the recent operating systems and propose to use the allocation methods for the video packetization. We empirically show that the proposed method can reduce the packetization overhead upto 28.3%, compared with the conventional sequential packetization method which have been widely used in Internet video transmission.

• Journal of the Korean Data and Information Science Society
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• v.24 no.1
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• pp.105-115
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• 2013

As far as the universities in south Korea are concerned, they have to meet the need of the situation as the number of the incoming students are decreasing because of the population-reducing in south Korea. The Ministry of Education Science and Technology is enforcing the restructuring of an universities by evaluating all the universities in Korea by using some indices (employment rate, supplement rate of students etc.). Most of the universities in Korea are widely permitting the changes of the major study as a method to improve the 'supplement rate of students' among some measures. These changes of major study (moving in and moving out) can give rise to difficulties in managing an university because there might be the departments with a small number of students as they moving out from low level departments to high level ones. Moreover, as raising the change rate of the major study, there is no loss from the university's point of view but a department could be in a difficult situation. The purpose of this study is to grasp the characteristics for changing major study by a general statistical analysis and graphs produced by a social network analysis with the D university's case. The results of this study are as follows; (a) category is from the engineering to humanity-society, (b) entrance level is from low to high, and (c) employment rate is from low to high as well.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.455-458
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• 2013

The conventional design of the information system architecture based on the personal experience of information systems has been acted as a limit in progress utilizing appropriate resource allocation and performance improvements. Architecture design depending on personal experience makes differences in variance of a designer's experience, intellectual level in related tasks and surroundings, and architecture quality according to individual's propensity. After all these problems cause a waste of expensive hardware resources. At working place, post-monitoring tools are diversely developed and are running to find the bottleneck and the process problems in the information operation. However, there are no simulation tools or models that are used for expecting and counteracting the problems at early period of designing architecture. To solve these problems we will first develop a simulation model for designing information system architecture in a pilot form, and will verify validity. If an error rate is found in the permissible range, then it can be said that the simulation reflects the characteristic of information system architecture. After the model is developed in a level that can be used in various ways, more accurate performance computation will be able to do, getting out of the old way relying on calculations, and prevent the existence of idle resources and expense waste that comes from the wrong design of architecture.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.343-353
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• 2011

The unsignalized intersections in a community road in the city of Seoul have 3,753 traffic accidents(9%) of total 41,702 cases in 2008, not high in the occurrence rate of traffic accidents, but seem to have a quite high potential of accidents due to the unreasonable and insufficient operation of systems and facilities in the part of traffic foundations. In particular, the un-signalized intersections in a community road have an insufficient measure for safety as compared to the crossroads with signals, and there are few analysis of traffic accidents and domestic researches on the model of affecting factors. Our country also has no concept of passing priority in operating a crossroad without signals, differently from foreign countries, so the researches and safety measures for improving the safety of a crossroad without signals in a community road are urgent. Therefore, This study set out to analyze the road conditions, traffic conditions, and traffic environment conditions on unsignalized intersection, to identify the elements that would impose obstructions in safety, and develop a traffic accident prediction model to evaluate the safety of an unsignalized intersection using the correlation between the elements and an accident. In addition, the focus was made on suggesting appropriate traffic safety policies by dealing with the danger elements in advance and on enhancing the safety on intersection in developing a traffic accident prediction model for an unsignalized intersection.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.9 no.1
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• pp.153-179
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• 1998

This study attempt to suggest a policy for the effect of using in the public libraries by the verification that are different between groups by their using patterns and types of book collections. by using patterns and system of desired-book for user. by using patterns and system of desired-book for user. The questionnaire is distributed to the delivery lending library's user and librarian in public libraries. The summary of results are as follows 1 The Circulation period of public library is one month per every delivery lending library. 2. The Circulation volume of public library is '100-200' books per every times. 3. There are significant differences by their using patterns and types of book collections. 4. There are significant differences by their using patterns and system of desired-book for user. 5. There are significant differences by their using patterns and placement of book collections. Their results show that library is most effective place of book collection services. 6. Circulation services must carry out only in the sphere of jurisdiction 7. A Lost books must set up treatment basis of natural reduction ratio 8. The Interference factors of delivery lending library are lacks of human power, lost books and negative attitute of user in order 9. The Effects of using a delivery lending library are a positive attitute and specialty of top management, the optimum of budget and the effect of deposit system 10. Natural reduction ratio of lost books appropriates 0.5-0.6% of total loaned books

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.115-122
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• 2002

This paper presents a new web cluster scheme based on dispatcher which does not depend on operating system for server and can examine server's status interactively. Two principal functions are proposed for new web cluster technique. The one is self-controlled load distribution and the other is transaction fail-safe. Self-controlled load distribution function checks response time and status of servers periodically, then it decides where the traffic goes to guarantee rapid response for every query. Transaction fail-safe function can recover lost queries including broken transaction immediately from server errors. Proposed new web cluster scheme is implemented by C language on Unix operating system and compared with legacy web cluster products. On the comparison with broadcast based web cluster, proposed new web cluster results higher performance as more traffic comes. And on the comparison with a round-robin DNS based web cluster, it results similar performance at the case of traffic processing. But when the situation of one server crashed, proposed web cluster processed traffics more reliably without lost queries. So, new web cluster scheme Proposed on this dissertation can give alternative plan about highly increasing traffics and server load due to heavy traffics to build more reliable and utilized services.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.855-859
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• 2011

The main pollutants from zirconium alloy tubing manufacturing process in nuclear industry are nitrate ($NO_3-N$) and fluoride (F-)Nitric acid, and hydrofluoric acid is used for acid pickling. The process for the removal of nitrate and fluoride is composed of 1st chemical coagulation, SOD (Sulfur Oxidation Denitrification) process using sulfur-oxidizing denitrification, and 2nd chemical coagulation. The characteristic of the wastewater treatment is an application of SOD process. The SOD Process is highly received attention because it is significantly different from existing processes for sulfur denitrification. A JSC (JeonTech-Sulfur- Calcium) Pellet is unification of sulfur and alkalinity material. According to result of SOD process in wastewater treatment plant, the removal efficiency of T-N was over 91% and the average concentration of T-N from influent was 147.55 mg T-N/L and that from effluent was 12.72 mg T-N/L. Therefore, SOD process is a useful to remove nitrogen from inorganic industrial wastewater and a new development of microbial activator was shown to be stable for activation of autotrophic bacteria.

• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.113-124
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• 2009

With increasing multicore system, much effort has been put on the performance improvement of its application. Because multicore system has multiple processing devices in one system, its processing power increases compared to the single core system. However in many cases the advantages of multicore can not be exploited fully because the existing software and hardware were designed to be suitable for single core. When the existing software runs on multicore, its performance improvement is limited by the bottleneck of sharing resources and the inefficient use of cache memory on multicore. Therefore, according as the number of core increases, it doesn't show performance improvement and shows performance drop in the worst case. In this paper we propose a method of performance improvement of multicore system by applying Flow-Level Parallelism to the existing TCP/IP network application and operating system. The proposed method sets up the execution environment so that each core unit operates independently as much as possible in network application, TCP/IP stack on operating system, device driver, and network interface. Moreover it distributes network traffics to each core unit through L2 switch. The proposed method allows to minimize the sharing of application data, data structure, socket, device driver, and network interface between each core. Also it allows to minimize the competition among cores to take resources and increase the hit ratio of cache. We implemented the proposed methods with 8 core system and performed experiment. Experimental results show that network access speed and bandwidth increase linearly according to the number of core.