• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.429-436
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• 2005

A mobile ad hoc network (MANET) is a collection of mobile nodes without any fixed infrastructure or my form of centralized administration such as access points and base stations. The ad hoc on-demand distance vector routing (AODV) protocol is an on-demand routing protocol for MANETs, which is one of the Internet-Drafts submitted to the Internet engineering task force (IETF) MANET working group. This paper proposes a new multipath routing protocol called maximally disjoint multipath AODV (MDAODV), which exploits maximally node- and link-disjoint paths and outperforms the conventional multipath protocol based on AODV as well as the basic AODV protocol. The key idea is to extend only route request (RREQ) message by adding source routing information and to make the destination node select two paths from multiple RREQs received for a predetermined time period. Compared to the conventional multipath routing protocol, the proposed MDAODV provides more reliable and robust routing paths and higher performance. It also makes the destination node determine the maximally node- and link-disjoint paths, reducing the overhead incurred at intermediate nodes. Our extensive simulation study shows that the proposed MDAODV outperforms the conventional multipath routing protocol based on AODV in terms of packet delivery ratio and average end-to-end delay, and reduces routing overhead.

• The KIPS Transactions:PartD
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• v.9D no.4
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• pp.587-602
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• 2002

Replicated database system was emerged to resolve the problem of reduction of the availability and the reliability due to the communication failures and site errors generated at centralized database system. But if update transactions are many occurred, the update is equally executed for all replicated data. Therefore, there are many problems the same thing a message overhead generated by synchronization and the reduce of concurrency happened because of delaying the transaction. In this paper, I propose a new concurrency control algorithm for enhancing the degree of parallelism of the transaction in fully replicated database designed to improve the availability and the reliability. To improve the system performance in the replicated database should be performed the last operations in the submitted site of transactions and be independently executed update-only transactions composed of write-only transactions in all sites. I propose concurrency control method to maintain the consistency of the replicated database and reflect the result of update-only transactions in all sites. The superiority of the proposed method has been tested from the respondence and withdrawal rate. The results confirm the superiority of the proposed technique over classical correlation based method.

• Journal of the Korean Geographical Society
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• v.29 no.2
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• pp.183-200
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• 1994

This research aims to introduce the theoretical basis of the studies of tourism resources, by review the research trends of tourism resources in the geography field. The geographical approaches to tourism resouces can be subdicided into 3 categories according to the subject. First, the classification of tourism resource types and the approach on the spatial distribution may be enumerated. This subject has been the object of the most interest and discussion to the geographers for tourism up to now. And from the viewpoint of contents, it has been developed by classifying the types of tourism resoures, which is based on the establishment of the range and standard of tourism resources and the spatial classification of types based on the distribution feature of the area. Second, the approach about cognition, preference and interpretation on the tourism resources as the background to induce tourism phenomenon and decide the tourism destination. Judging from the fact that most of this subject is starting from the behavioural study and that the right understanding and interpretation of tourism resource is the important factor to decide the preference degree of tourists, we have to have much interest about the field of tourism geoaraphy. Third, the development of tourism resources which is showing the active study recently and its influence and effect attendant upon it may be enumerated. Today, as the economic value of tourism is become important internationally, tourism resources are recognized as the important factor to induce the industrialization of tourism. And in the series of analytical studies related to it the interest has been transferred from the economic benefit analysis attendant upon tourism development including tourism resource and to the cultural, educational, environmental and psychological influence, etc. As the result of composite examination, for the geographical studies about tourism resources, the spatial scale and the contents are being subdivided and specialized. And in the side of subject and method of study, it is developing into the positive study based on the concrete data and the measuring and analytical frame.

• Economic and Environmental Geology
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• v.49 no.3
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• pp.213-224
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• 2016

Non-conventional resource and alternative energy were researched for predicting oil peak. In this study, one of many non-conventional resources, specifically oil-sands, was investigated due to the increasing interest of oil-sands plant modularization in permaforst areas for reducing the construction periods through modular transportation while limiting local construction workers. Hence, tehcnological trends were analyzed for oil-sand plant modularization. Data used were between 1994 and 2015 for patent analysis while targets included Korea, US, Japan, Europe and Canada. Technology classification system consisted of mining, steam assisted gravity drainage(SAGD), separation/upgrading/tailors ponds, module design/packaging, module transportation and material/maintenance. Result of patent analysis, patent application accounts 89% in US and Canada. The main competitive companies were Shell, Suncor and Exxon-mobil. Unlike other oil developments, oil-sands have a long-term stable production characteristic, hence, it is important to ensure the competitiveness of oil-sands for obtaining a patent in the long run.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.6
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• pp.580-586
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• 2017

The establishment of big data service environment requires both cloud-based network technology and clustering technology to improve the efficiency of information access. These cloud-based networks and clustering environments can provide variety of valuable information in real-time, which can be an intensive target of attackers attempting illegal access. In particular, attackers attempting IP spoofing can analyze information of mutual trust hosts constituting clustering, and attempt to attack directly to system existing in the cluster. Therefore, it is necessary to detect and respond to illegal attacks quickly, and it is demanded that the security policy is stronger than the security system that is constructed and operated in the existing single system. In this paper, we investigate routing pattern changes and use them as detection information to enable active correspondence and efficient information service in illegal attacks at this network environment. In addition, through the step-by -step encryption based on the routing information generated during the detection process, it is possible to manage the stable service information without frequent disconnection of the information service for resetting.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2719-2726
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• 2010

The purpose of this study was to investigate the scientific basic grounds for the assessment of health and environmental diseases resulting from air pollutants in Pohang. For this study, we investigated pollutants, weather characteristics and concentration distribution of fine particles ($PM_10$) yearly and each season, using data from Air Quality Monitoring Stations. The properties of concentration distribution and seasonal fluctuation of $PM_10$ were studied qualitatively and quantitatively using CALPUFF, air dispersion model. The average concentration of $PM_10$ for each season was spring($75.7{\mu}g/m^3$)>summer($56.8{\mu}g/m^3$)>winter($53.6{\mu}g/m^3$)>fall( $52.7{\mu}g/m^3$). In the case of spring, high concentrations appear due to the Asian dust frequently occurring. The contributions of $PM_10$ classified by the types of pollution source in Pohang were point source 62%>mobile source 33%>area source 5%. An important point is that 97% of emissions were produced from the iron manufacture in steel industry. Therefore, it is necessary to control the emission sources of pollutants and to construct an observation system at Pohang steel industrial complex from now on. It’s time to control the risk factors for health and environmental disease to protect the health of resident in Pohang and its neighboring areas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1176-1187
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• 2014

In Contemporary residential area, especially apartment commplex, crime affect the quality of life and sustainability of cities. So our interest is an all-time high in the role that planning processes and the design of the physical environment can play in reducing the opportunity for crime. The purpose of this study try to find the possibility of application of CPTED in Urban Apartment Complex. Recently, as increase of residencial density, diverse and new types of crime are increasing in urban apartment complex. It is the current of times which demand our serious consideration. This research focused on crime reduction through the physical environmental control methods. And the concepts and contents of CPTED are studied and the case studies of developed countries are surveyed. For groping in the practical application, researched into the case study of apartment blocks in medium sized city, Cheongju. Also Local crime prevention initiatives require partnership working, both between professionals and with local communities. The result of this study has implicated, increasing importance on daily safety issue in urban life and examining the possibility of applying crime prevention and reduction program and systems.

• The KIPS Transactions:PartA
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• v.16A no.2
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• pp.101-112
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• 2009

Existing techniques for defragmentation of the file system need intensive disk operation for some periods at specific time such as disk defragmentation program. In this paper, for solving this problem, we design and implement the automatic and continuous defragmentation free system by distributing the disk operation. We propose the Automatic Layout Scoring(ALS) mechanism for measuring defragmentation degree and suggest the Lazy Copy mechanism that copies the defragmented data at idle time for scattering the disk operation. We search the defragmented file by Automatic Layout Scoring mechanism and then find for empty spaces for that searched file. After lazy copy of searched fils to empty space for preventing that file from being lost, the algorithm solves the defragmentation problem by updating the I-node of that file. We implement these algorithms in Linux and evaluate them for small and defragmented file to get the layout scoring. We outperform the Linux EXT2 file system by $2.4%{\sim}10.4%$ in layout scoring evaluation. And the performance of read and write for various file size is better than the EXT2 by $1%{\sim}8.5%$ for write performance and by $1.2%{\sim}7.5%$ for read performance. We suggest this system for solving the problem of defragmentation automatically without disturbing the I/O task and manual management.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.17-28
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• 2010

A climbing lane is installed to separate low-speed traffic from high-speed traffic if drastic traffic capacity reduction is expected due to a large number of vehicles that slow down in the upward section. Existing studies on climbing lanes have focused on the designation, location of starting and ending points, and installation method of climbing lane with regard to road design standards. However, in terms of traffic operation, it was known that the climbing lanes cause traffic congestion due to the increase of traffic volumes. In this regard, this study aims to establish traffic operational guidance as to how much effects temporary closure of climbing lanes can have on traffic improvement according to the volume-capacity ratio, grade, and composition of trucks. A test section of simulated climbing lane was selected in Nakdong JC bound for Masan(136.9K~133.3K, 3.6km, 3.7%) on Jungbunaeryuk expressway to conduct VISSIM analyses, microscopic traffic simulation based on such control variables as traffic volume(v/c), grade and the trucks ratio. As a result of the analyses, it has been found that v/c and the ratio of trucks are the key variables for efficient traffic management of climbing lanes in order to relieve traffic congestion via climbing lane. If ratio of trucks are more than 50% and when v/c would be 0.8, both climbing lane would be closed and non-operated regardless of grade and ratio of trucks when v/c is 1.0. With the increased traffic due to a five-day work week system, continued peak hours during the weekday, increased and various patterns of congestion on expressway, this study would be expected to contribute to facilitating researches on flexible operational standards for road facilities.

• Journal of Soil and Groundwater Environment
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• v.11 no.5
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• pp.9-19
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• 2006

The accurate estimation of groundwater recharge is important for the proper management of groundwater systems. The widely used techniques of groundwater recharge estimation include water table fluctuation method, baseflow separation method, and annual water balance method. However, these methods can not represent the temporal-spatial variability of recharge resulting from climatic condition, land use, soil storage and hydrogeological heterogeneity because the methods are all based on the lumped concept and local scale problems. Therefore, the objective of this paper is to present an effective method for estimating groundwater recharge with spatial-temporal variability using the SWAT model which can represent the heterogeneity of the watershed. The SWAT model can simulate daily surface runoff, evapotranspiration, soil storage, recharge, and groundwater flow within the watershed. The model was applied to the Musimcheon watershed located in the upstream of Mihocheon watershed. Hydrological components were determined during the period from 2001 to 2004, and the validity of the results was tested by comparing the estimated runoff with the observed runoff at the outlet of the catchment. The results of temporal and spatial variations of groundwater recharge were presented here. This study suggests that variations in recharge can be significantly affected by subbasin slope as well as land use.