• Wind and Structures
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• v.38 no.2
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• pp.129-146
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• 2024

Aiming at the problem of non-stationary wind field simulation of downbursts, a non-stationary down-burst generation system was designed by adding a nozzle and program control valve to the inlet of the original wall jet model. The computational fluid dynamics (CFD) method was used to simulate the downburst. Firstly, the two-dimensional (2D) model was used to study the outflow situation, and the database of working conditions was formed. Then the combined superposition of working conditions was carried out to simulate the full-scale measured downburst. The three-dimensional (3D) large eddy simulation (LES) was used for further verification based on this superposition condition. Finally, the wind tunnel test is used to further verify. The results show that after the valve is opened, the wind ve-locity at low altitude increases rapidly, then stays stable, and the wind velocity at each point fluctuates. The velocity of the 2D model matches the wind velocity trend of the measured downburst well. The 3D model matches the measured downburst flow in terms of wind velocity and pulsation characteris-tics. The time-varying mean wind velocity of the wind tunnel test is in better agreement with the meas-ured time-varying mean wind velocity of the downburst. The power spectrum of fluctuating wind ve-locity at different vertical heights for the test condition also agrees well with the von Karman spectrum, and conforms to the "-5/3" law. The vertical profile of the maximum time-varying average wind veloci-ty obtained from the test shows the basic characteristics of the typical wind profile of the downburst. The effectiveness of the downburst generation system is verified.

• Journal of Korean Society of Archives and Records Management
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• v.8 no.2
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• pp.39-60
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• 2008

This paper deals with the four aspects of the acquisition, construction and common use of modern and post-modern document DB in the NAK, NIKH, and AKS. First, The concept of Korean regional history includes provincial history, local history and regional history and as far as modern and post-modern history is concerned, the concept of regional history is on expansion. Second, National Archives of Korea has been systematically collecting and managing modern and post-modern regional history records in compliance to Public Institutes Records Management Law, enacted in 1999 and currently is in charge of handling public records of 373 central government administration offices, 514 regional government offices, Office of Education, universities and of other public agencies. National Institute of Korean History is working on a ten year project from 2004 to collect the scattered modern and post-modern regional history records and to classify them regionally and thematically. The Academy of Korean Studies has been collecting modern and post-modern regional history records and collection was initiated by Modern History Research. Those records that are collected from 1997 and 2005 are mainly from the liberation period. Third, characteristics of Central Archives Management System and Nara Records Portal System of NAK, Korean History Database System of NIKH and of The AKS' Korean Provincial Culture Electronic Encyclopedia are elaborated. Fourth, establishing 'Modern and Post-modern Regional History Records Council' as an affiliated organization of National Archives Management Committee is recommended, NAK leading the council and promoting further cooperation. In this section, an emphasis on allotted tasks of three institutes in order to achieve technology development for digitalized resource sharing, to improve on contents and to promote public and international use is placed as well.

• Journal of Korea Water Resources Association
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• v.56 no.6
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• pp.403-417
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• 2023

In this research, a methodology was developed for constructing an appropriate rainfall image database for estimating rainfall intensity based on CCTV video. The database was constructed in the Large-Scale Climate Environment Chamber of the Korea Conformity Laboratories, which can control variables with high irregularity and variability in real environments. 1,728 scenarios were designed under five different experimental conditions. 36 scenarios and a total of 97,200 frames were selected. Rain streaks were extracted using the k-nearest neighbor algorithm by calculating the difference between each image and the background. To prevent overfitting, data with pixel values greater than set threshold, compared to the average pixel value for each image, were selected. The area with maximum pixel variability was determined by shifting with every 10 pixels and set as a representative area (180×180) for the original image. After re-transforming to 120×120 size as an input data for convolutional neural networks model, image augmentation was progressed under unified shooting conditions. 92% of the data showed within the 10% absolute range of PBIAS. It is clear that the final results in this study have the potential to enhance the accuracy and efficacy of existing real-world CCTV systems with transfer learning.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.4
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• pp.5-22
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• 1997

The purpose of the study was to development an information delivery system for the home nursing service, to demonstrate and to evaluate the efficiency of it. The period of research conduct was from September 1996 to August 31, 1997. At the 1st stage to achieve the purpose, Firstly Assessment tool for the patients with cerebral vascular disease who have the first priority of HNS among the patients with various health problems at home was developed through literature review. Secondly, after identification of patient nursing problem by the home care nurse with the assessment tool, the patient's classification system developed by Park (1988) that was 128 nursing activities under 6 categories was used to identify the home care nurse's activities of the patient with CAV at home. The research team had several workshops with 5 clinical nurse experts to refine it. At last 110 nursing activities under 11 categories for the patients with CVA were derived. At the second stage, algorithms were developed to connect 110 nursing activities with the patient nursing problems identified by assessment tool. The computerizing process of the algorithms is as follows: These algorithms are realized with the computer program by use of the software engineering technique. The development is made by the prototyping method, which is the requirement analysis of the software specifications. The basic features of the usability, compatibility, adaptability and maintainability are taken into consideration. Particular emphasis is given to the efficient construction of the database. To enhance the database efficiency and to establish the structural cohesion, the data field is categorized with the weight of relevance to the particular disease. This approach permits the easy adaptability when numerous diseases are applied in the future. In paralleled with this, the expandability and maintainability is stressed through out the program development, which leads to the modular concept. However since the disease to be applied is increased in number as the project progress and since they are interrelated and coupled each other, the expand ability as well as maintainability should be considered with a big priority. Furthermore, since the system is to be synthesized with other medical systems in the future, these properties are very important. The prototype developed in this project is to be evaluated through the stage of system testing. There are various evaluation metrics such as cohesion, coupling and adaptability so on. But unfortunately, direct measurement of these metrics are very difficult, and accordingly, analytical and quantitative evaluations are almost impossible. Therefore, instead of the analytical evaluation, the experimental evaluation is to be applied through the test run by various users. This system testing will provide the viewpoint analysis of the user's level, and the detail and additional requirement specifications arising from user's real situation will be feedback into the system modeling. Also. the degree of freedom of the input and output will be improved, and the hardware limitation will be investigated. Upon the refining, the prototype system will be used as a design template. and will be used to develop the more extensive system. In detail. the relevant modules will be developed for the various diseases, and the module will be integrated by the macroscopic design process focusing on the inter modularity, generality of the database. and compatibility with other systems. The Home care Evaluation System is comprised of three main modules of : (1) General information on a patient, (2) General health status of a patient, and (3) Cerebrovascular disease patient. The general health status module has five sub modules of physical measurement, vitality, nursing, pharmaceutical description and emotional/cognition ability. The CVA patient module is divided into ten sub modules such as subjective sense, consciousness, memory and language pattern so on. The typical sub modules are described in appendix 3.

• Journal of Intelligence and Information Systems
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• v.17 no.2
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• pp.39-60
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• 2011

Since the introduction of web 2.0 technology, social network service has been recognized as the foundation of an important future information technology. The advent of web 2.0 has led to the change of content creators. In the existing web, content creators are service providers, whereas they have changed into service users in the recent web. Users share experiences with other users improving contents quality, thereby it has increased the importance of social network. As a result, diverse forms of social network service have been emerged from relations and experiences of users. Social network is a network to construct and express social relations among people who share interests and activities. Today's social network service has not merely confined itself to showing user interactions, but it has also developed into a level in which content generation and evaluation are interacting with each other. As the volume of contents generated from social network service and the number of connections between users have drastically increased, the social network extraction method becomes more complicated. Consequently the following problems for the social network extraction arise. First problem lies in insufficiency of representational power of object in the social network. Second problem is incapability of expressional power in the diverse connections among users. Third problem is the difficulty of creating dynamic change in the social network due to change in user interests. And lastly, lack of method capable of integrating and processing data efficiently in the heterogeneous distributed computing environment. The first and last problems can be solved by using FOAF, a tool for describing ontology-based user profiles for construction of social network. However, solving second and third problems require a novel technology to reflect dynamic change of user interests and relations. In this paper, we propose a novel method to overcome the above problems of existing social network extraction method by applying FOAF (a tool for describing user profiles) and RSS (a literary web work publishing mechanism) to OLAP system in order to dynamically innovate and manage FOAF. We employed data interoperability which is an important characteristic of FOAF in this paper. Next we used RSS to reflect such changes as time flow and user interests. RSS, a tool for literary web work, provides standard vocabulary for distribution at web sites and contents in the form of RDF/XML. In this paper, we collect personal information and relations of users by utilizing FOAF. We also collect user contents by utilizing RSS. Finally, collected data is inserted into the database by star schema. The system we proposed in this paper generates OLAP cube using data in the database. 'Dynamic FOAF Management Algorithm' processes generated OLAP cube. Dynamic FOAF Management Algorithm consists of two functions: one is find_id_interest() and the other is find_relation (). Find_id_interest() is used to extract user interests during the input period, and find-relation() extracts users matching user interests. Finally, the proposed system reconstructs FOAF by reflecting extracted relationships and interests of users. For the justification of the suggested idea, we showed the implemented result together with its analysis. We used C# language and MS-SQL database, and input FOAF and RSS as data collected from livejournal.com. The implemented result shows that foaf : interest of users has reached an average of 19 percent increase for four weeks. In proportion to the increased foaf : interest change, the number of foaf : knows of users has grown an average of 9 percent for four weeks. As we use FOAF and RSS as basic data which have a wide support in web 2.0 and social network service, we have a definite advantage in utilizing user data distributed in the diverse web sites and services regardless of language and types of computer. By using suggested method in this paper, we can provide better services coping with the rapid change of user interests with the automatic application of FOAF.

• Journal of Internet Computing and Services
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• v.16 no.1
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• pp.67-74
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• 2015

In recent years, frequent itemset mining for considering the importance of each item has been intensively studied as one of important issues in the data mining field. According to strategies utilizing the item importance, itemset mining approaches for discovering itemsets based on the item importance are classified as follows: weighted frequent itemset mining, frequent itemset mining using transactional weights, and utility itemset mining. In this paper, we perform empirical analysis with respect to frequent itemset mining algorithms based on transactional weights. The mining algorithms compute transactional weights by utilizing the weight for each item in large databases. In addition, these algorithms discover weighted frequent itemsets on the basis of the item frequency and weight of each transaction. Consequently, we can see the importance of a certain transaction through the database analysis because the weight for the transaction has higher value if it contains many items with high values. We not only analyze the advantages and disadvantages but also compare the performance of the most famous algorithms in the frequent itemset mining field based on the transactional weights. As a representative of the frequent itemset mining using transactional weights, WIS introduces the concept and strategies of transactional weights. In addition, there are various other state-of-the-art algorithms, WIT-FWIs, WIT-FWIs-MODIFY, and WIT-FWIs-DIFF, for extracting itemsets with the weight information. To efficiently conduct processes for mining weighted frequent itemsets, three algorithms use the special Lattice-like data structure, called WIT-tree. The algorithms do not need to an additional database scanning operation after the construction of WIT-tree is finished since each node of WIT-tree has item information such as item and transaction IDs. In particular, the traditional algorithms conduct a number of database scanning operations to mine weighted itemsets, whereas the algorithms based on WIT-tree solve the overhead problem that can occur in the mining processes by reading databases only one time. Additionally, the algorithms use the technique for generating each new itemset of length N+1 on the basis of two different itemsets of length N. To discover new weighted itemsets, WIT-FWIs performs the itemset combination processes by using the information of transactions that contain all the itemsets. WIT-FWIs-MODIFY has a unique feature decreasing operations for calculating the frequency of the new itemset. WIT-FWIs-DIFF utilizes a technique using the difference of two itemsets. To compare and analyze the performance of the algorithms in various environments, we use real datasets of two types (i.e., dense and sparse) in terms of the runtime and maximum memory usage. Moreover, a scalability test is conducted to evaluate the stability for each algorithm when the size of a database is changed. As a result, WIT-FWIs and WIT-FWIs-MODIFY show the best performance in the dense dataset, and in sparse dataset, WIT-FWI-DIFF has mining efficiency better than the other algorithms. Compared to the algorithms using WIT-tree, WIS based on the Apriori technique has the worst efficiency because it requires a large number of computations more than the others on average.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.333-340
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• 2015

Because soils in reclaimed lands nearby coastal areas have much higher salinity and moisture content than soils in inland area, parts of greenhouses embedded in such soils are exposed to highly corrosive environments. Owing to the accelerated corrosion of galvanized steel pipes for substrucrture and structure of greenhouses in saline environments, repair and reinforcement technologies and efficient maintenance and management for the construction materials in such facilities are required. In this study, we measured the corrosion rates of the parts used for greenhouse construction that are exposed to the saline environment to obtain a basic database for the establishment of maintenance and reinforcement standards for greenhouse construction in reclaimed lands with soils with high salinity. All the test pipes were exposed to soil and water environments with 0, 0.1, 0.3, and 0.5% salinity during the observation period of 480 days. At the end of the observation period, salinity-dependent differences of corrosion rate between black-surface corrosion and relatively regular corrosion were clearly manifested in a visual assessment. For the soils in rice paddies, the corrosion growth rate increased with salinity (0.008, 0.027, 0.036, and $0.043mm{\cdot}yr^{-1}$ at 0, 0.1, 0.3, and 0.5% salinity, respectively). The results for the soils in agricultural fields are 0.0002, 0.039, 0.040, and $0.039mm{\cdot}yr^{-1}$ at 0, 0.1, 0.3, and 0.5% salinity, respectively. The higher corrosion rate of rice-paddy soil was associated with the relatively high proportion of fine particles in it, reflecting the general tendency of soils with evenly distributed fine particles. Hence, it was concluded that thorough measures should be taken to counteract pipe corrosion, given that besides high salinity, the soils in reclaimed lands are expected to have a higher proportion of fine particles than those in inland rice paddies and agricultural fields.

• Journal of the Korean Geographical Society
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• v.43 no.4
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• pp.620-637
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• 2008

$Che{\breve{o}}n$ (提堰) refers to the irrigation facilities used to provide water to the land on which rice is farmed. As the maintenance of $Che{\breve{o}}n$ required great amounts of capital, labor, and technology, the construction and maintenance of such facilities was controlled by the government. $Che{\breve{o}}n$ was perceived as being of particular importance during the $Che{\breve{o}}n$ era, which adopted agriculture as the basis of state management. Therefore, the management of $Che{\breve{o}}n$ was considered to be one of the main state policies. This is why $Che{\breve{o}}n$-related records can often be found in the historical documents written during the $Che{\breve{o}}n$ era. As such historical documents in the form of Jiriji (地理誌, geographical descriptions) include detailed descriptions of the number, size, and location of $Che{\breve{o}}n$ in individual counties($kunby{\breve{o}}n$), these help to conduct comprehensive analysis of the state of $Che{\breve{o}}n$ during the $Che{\breve{o}}n$ era. Based on these facts, this study attempts to establish a database of the $Che{\breve{o}}n$-related contents included in the <$Y{\breve{o}}jitos{\breve{o}}$(與地圖書)> published during the latter period of $Che{\breve{o}}n$, and using the established database, to identify the regional characteristics of $Che{\breve{o}}n$. More precisely, by analyzing the state of the distribution of $Che{\breve{o}}n$ at the national level, an effort was made to review the regional characteristics of $Che{\breve{o}}n$ in terms of their distribution and of the natural geographical conditions found in the locales where $Che{\breve{o}}n$ were located, as well as of the interrelation between such $Che{\breve{o}}n$ and socioeconomic factors such as the scale of the population and the size of the area under cultivation. Other factors which were delved into included matters related to the size of $Che{\breve{o}}n$ such as their perimeter, length, and scale of the area which they irrigated, the characteristics of the locales where $Che{\breve{o}}n$ were located, and the regional differences in the characteristics of $Che{\breve{o}}n$.

• Korean Journal of Remote Sensing
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• v.33 no.5_3
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• pp.867-878
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• 2017

Recent interest in geological heritage has been increased in that it can be used as a basic data onto predicting the global environmental change of its containing information about past global environment. In addition, due to the characteristics of the geological heritage, it is easy to damage and difficult to recover without continuous preservation and management. However, there are more damages occurring because of the sporadic spatial distribution and ambiguous management authority of geological heritage. Therefore, an integrated management system is needed by determining the spatial distribution of geological heritage preferentially. In this study, the detailed criteria for assessment of value from the preliminary studies were applied and the geological heritage grade distribution map was generated by using geospatial data in Seoul metropolitan area. For this purpose, the list of geological heritage sites in the Seoul metropolitan area, which is the study area, were complied through a literature review. The geospatial database was designed and constructed by applying the detailed criteria for assessment of value from the preliminary studies. After the construction of the spatial database, a grade map of the geological heritage was created. As a result of the geological heritage grade map in the Seoul metropolitan area, there were more than 35% of the geological heritage in northern Gyeonggi provinces such as Yeoncheon city (18.8%), Pocheon city (10.6%) and Paju city (6.3%). It is followed by 18.1% in Incheon and 8.1% in Ansan, which is approximately 26.2% in western Gyeonggi Province. The geological age of the geological heritage was the highest at in the fourth stage of the Cenozoic era of 16.9%. Through the results of this study, the geological heritage data of the Seoul metropolitan area were extracted from existing literature data and converted into spatial information. It enables comparing the geological features with the spatial distribution of geological heritage. In addition, a management system has been established based on spatial information of constantly building geological heritage data. This provides the integrated management system of the geological heritage to manage authority so that it can be used as a basis for the development of the geological park. Based on the results of this study, it is considered to be possible to systematically construct and utilize the geological heritage across the country.

• Journal of Korea Spatial Information System Society
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• v.2 no.2 s.4
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• pp.5-23
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• 2000

Since 1995, national and local governments have competitively initiated many and large GIS projects and audit for the projects becomes an important issue. So far, the audit in the Information Technology(IT) area has tried to deal with the issue but ineffectiveness has been found for the successful GIS project management. Effective auditing is a critical element for the project management. In order to establish a proper audit model for the GIS projects and to promote auditing activities in the projects, this study constructs two hypotheses and tries to prove them. The hypotheses are as follows : 1) For a good audits model for GIS, unique characteristics of a GIS project audit items and the scope of the audit need to be identified. 2) The scope of audit needs to be classified according to the requests from tasks in the projects. To prove the hypotheses, this study analyzes positive aspects of audit in IT and construction projects, clarifies the audit items in GIS projects by comparing with them, and classifies the scope of the GIS audit based on various types of GIS projects. As a results, 5 types of the GIS audit are identified : (1) audit for project management, (2) audit focused on IT, (3) audit characterized by GIS technologies, (4) GIS database audit and (5) consulting services for critical problems in the projects. In addition, 4 criteria in classifying the GIS projects are suggested for the GIS audit. The 4 criteria are domain, scope, duration, and GIS applications technologies. Especially, GIS technology considered in this study includes GIS software, methodologies for GIS development, GIS database and quality control of GIS data, which are not usually reflected in the existing studies about in GIS audit. Because the GIS audit depends on a type of GIS projects, scopes of the audit can be flexibly reconstructed in accordance with the types of GIS projects. This is a key to effective and realistic audit for the future GIS projects. Strategies for effective GIS audit are also proposed in terms of the following: GIS project management, goal establishment in each audit stage, documentation from GIS audit, timing strategies for intensive GIS audit, and designing team structure.