• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.1
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• pp.23-34
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• 2012

Space launch vehicles are designed to fly according to the elaborate pre-determined path. However, if a vehicle went out of the planned trajectory or its thrust terminated abnormally, or if a free-fall atmospheric reentry vehicle tracked by a tracking sensor became impossible to be measured, it is required to attempt to track by a another track equipment or estimate its impact point rapidly. In this paper a new algorithm is proposed, named the ITS-EKF combined with the Integrated Track Splitting (ITS) algorithm and the Extended Kalman Filter (EKF) to obtain the location information of a ballistic projectile without thrust, create its track and maintain it in an environment with clutter. For the reentry vehicle, the track performance is to be verified and the impact point is estimated by applying the simulation through ITS-EKF algorithm. To ensure the proposed algorithm's adequacy, by comparing the track performance and impact point distribution by the ITS-EKF with those of ITS-PF combined with ITS and Particle Filter (PF), it is confirmed that the ITS-EKF algorithm can be used an effective real-time On-line impact point prediction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.193-199
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• 2017

The purpose of this study was to provide basic data for the development of fall prevention programs for the elderly and for improvement of quality of life based on history of falls, chronic diseases, location, fear of falling, daily living activities, and quality of life. This study was conducted from 15th August to 17th September of 2016 on 185 elderly subjects above the age of 65 living in four centers of J city and four centers of J rural. The results of this study are as follows: There were no statistically significant differences in daily living activities, fear of falls, and quality of life regarding falls in the past. There were statistically significant differences in fear of falling and quality of life regarding chronic diseases. There were statistically significant differences in daily living activities and quality of life regarding residence. This study confirms that there were relations among daily living activities, fear of falling, and quality of life, and there was a negative correlation between fear of falling and accomplishment of daily living activities(r=-.386, p<.000). There was also a positive correlation between accomplishment of daily living activities and quality of life(r=.513, p<.000). Therefore, avoiding outings on slippery roads and creating safe environments for the elderly are important to reduce fear of falling. Additionally, a system should be developed for the elderly to acquire necessary information for daily life.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.135-139
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• 2007

Recently Data Centric Storage (DCS) schemes are variously studied for several applications (e.g. natural environment investigation, military application systems and environmental changes monitoring). In DCS scheme, data is stored at nodes within the network by name. There are several drawbacks in the existing schemes. The first is the inefficiency of the range query processing on not considered the locality of store point. the second is the non-homogeneity of store load of each sensors in case of the sensor distribution density is non-uniformed. In this paper, we propose a novel data centric storage scheme with the sensor distribution density which satisfied with the locality of data store location. This scheme divides whole sensor network area using grid and distributes the density bit map witch consist of the sensor density information of each cell. sensors use the density bit map for storing and searching the data. We evaluate our scheme with existing schemes. As a result, we show improved load balancing and more efficient range query processing than existing schemes in environment which sensors are distributed non-uniform.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6427-6433
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• 2013

For trains to run safely and quickly, the train should always follow the preceding train at a proper spacing. For this purpose, a certain distance between the stations is set for each block section. For the safe operation of trains in one block section, only one train service for an automatic block system is needed. The existing block system is composed an ABS, which is a linked track circuit and line sideway system through the interlocking system. The interlocking system is being replaced with a domestic electronic interlocking system. On the other hand, the block system still uses the relay format of an analog system, and is independently installed of the line sideway systems. Therefore, the existing block system has many problems in terms of construction and maintenance. In addition, the existing domestic line is used for ABS and LEU , which is installed separately, despite the train being controlled by the information of the same signal at the same location. This is not efficient in terms of each product price and the maintenance costs. This paper introduces an integrated electronic block system and the field test results. The field test was carried out through a periodic inspection performed eight times from January to late August.

• Journal of Navigation and Port Research
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• v.31 no.6
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• pp.479-484
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• 2007

For calculation of wave field for design of coastal and port structures, generally the wind fields from inland observation record or the predicted waves from deep water wave transformation model are being used. However, for the first case, as we should revise the wave data adopting correcting parameters depending on the distance from the coast and location, it is difficult to extract water waves from wind field. Furthermore, for the second case, because of the calculation which executed under very large grid sizes in the wide domain, the simulation(wave transformation) implied uncertainty in the near shore area and shallow region. So it's difficult to obtain exact data from the simulation. Thus, in this study the calculation of wave field on shallow water is accomplished using the observed data of typhoon 'Maemi' in the Korea Eastern South sea. Moreover, for the accuracy of the calculated wave field, we compared and studied the observed data of wave height and direction on the vicinity of the Ulsan waters. It is proved that the results of this study is more accurate than the existing method with showing ${\pm}1.3%$ difference between observed and calculated wave height distribution in Ulsan waters

• Journal of Korean Library and Information Science Society
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• v.9
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• pp.241-266
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• 1982

This paper gives a summary and overview of a survey conducted at the catalogues of five universities in Daegu during November 1982. The major objective of this study was to secure information about user needs in order to improve the catalogue in Korean university libraries. Data was collected by a combined method of questionnaire and interview. A total of 379 respondents were taken on a randomly selected sample of catalogue users. Results of the survey can be summarized as follows: 1. Eighty-eight percent of the students answered that they had used the library more than twice a month. Nevertheless the number of students consulting the catalogue with the same frequency was only 220, or a n.0, pproximately 58 percent. Those who used the library most tended to use the catalogue more than those who rarely came to the library. 2. Those who had been shown how to use their own catalogue were only 32.5percent of which the students found the instruction sufficient for them to be able to use the catalogue were only 37.5 percent. In particular, they stated that instructions by printed materials and/or library orientation were so poor that they didn't give much help in using the catalogue. This problem makes many libraries to review their own method of instruction in order to encourage patrons to use the catalogue more effectively. 3. Most of the students consulted the catalogue in order to locate library materials. Known-item searches and subject searches were 84 and 16 percent respectively. While 70.5 percent of the students used the author-title catalogue without any difficulties, only 35.5 percent of those stated that using the classed catalogue was easy. 4. It was surprising that the number of students using title access in the search was far greater than that of students using author access. In contrast with this, other studies conducted by many earlier overseas investigators revealed that the great majority of patrons tended to use the latter first. Therefore, we should put more emphasis on the title entries in the catalogue itself as well as cataloging rules. 5. Most useful bibliographic elements in the entry were author, title, call number, date and publisher whereas edition, series statement and the location of publisher were rarely used compared with the other elements. Content note was the most desirable element in the entry to be involved, for many catalogers were used not to describe it on the note area. 6. The chief reason given for not using the catalogue was "I can manage without it" with "It's difficult to understand contents of the card entry." The other one was "It's useless to search materials by the catalogue because I've failed so many times to obtain them out of the stock." In response to this, circulation and acquisition system should be improved not to make such complaints any more.

• Progress in Medical Physics
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• v.9 no.1
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• pp.1-9
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• 1998

In order to provide complementary image data, CT(computed tomography), MR(magnetic resonance) and angiography have been used in the field of Stereotactic Radiosurgery(SRS) and neurosurgery. The aim of this work is to develop 3-D stereotactic localization system in order to determine the precise shape, size and location of the lesion in the brain in the field of Stereotactic Radiosurgery(SRS) and neurosurgery using multi-image modality and multi purpose QA phantom. In order to obtain accurate position of a target, Hitchcoke stereotactic frame and CT/angiography localizers were rigidly attached to the phantom with nine targets dispersed in 3-D space. The algorithms to obtain a 3-D stereotactic coordinates of the target have been developed using the images of the geometrical phantom which were taken by CT/angiography. Positions of targets computed by our algorithms were compared to the absolute position assigned in the phantom. Outlines of targets on each CT image were superimposed each other on angiography images. A spatial mean distance errors were 1.02${\pm}$0.17mm for CT with a 512${\times}$512 matrix and 2mm slice thickness, 0.41${\pm}$0.05mm for angiogra- phy localization. The resulting accuracy in the target localization suggests that the developed system has enough Qualification for Stereotactic Radiosurgery (SRS).

• Journal of the Korean Geographical Society
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• v.45 no.1
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• pp.165-183
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• 2010

For the study of the development of Asia map made by european map makers, one should consider Gog and Magog which existed in the maps for more than 700 years. Gog and Magog are described as an apocalyptic people in the Bible and medieval literature, and they are important elements in medieval mappaemundi and early modem world maps. This study classified representation types of Gog and Magog in old western maps. Maps were classed in to six categories according to the location and ethnic groups which they represent, and they were discussed in cartographic context. The maps until the fourteenth century place Gog and Magog, shut up by Alexander, near Caspian Sea. In the fifteenth century, Gog and Magog were described as Closed Jews in maps. From the sixteenth century they appear in the far northeastern part of Asia and they are named as Amagog or Ung and Mongul. In the mid-seventeenth century, they are located in Eastern Siberia by French cartographers. But with the expansion of geographic knowledge, Gog and Magog disappeared completely in the eighteenth century. In general, God and Magog were represented on the basis of traditional lore rather than on the Bible, and they became one means of mapping others of European community.

• Journal of Gastric Cancer
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• v.8 no.2
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• pp.104-109
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• 2008

Purpose: To investigate the clinicopathlogical characteristics and the surgical methods for gastric submucosal tumors in Korea, the Information Committee of the Korean Gastric Cancer Association performed a nationwide survey. Materials and Methods: Data on 878 patients who underwent resection from 2005 to 2006 were collected from medical records obtained from 47 institutes. Diagnosis, demographics, symptoms, tumor factors (location, size, degree of malignancy) and operative factors (surgicalmethod and approach, mortality) were analyzed. Results: Gastrointestinal stromal tumors (GISTs) were the most common cancers (n=586, 66.8%), followed by leiomyomas (n=97, 11.1%), schwannomas (n=70, 8.0%), ectopic pancreas (n=67, 7.8%) and carcinoids (n=16, 1.8%). The mean age of patients was 56.0 years and the male to female ratio was 1:1.18. Only 40.9% of the patients had symptoms at the time of diagnosis, such as abdominal pain, dyspepsia and bleeding. Gastric submucosal tumors were most frequently located in the upper third of the stomach and 55.4% of the GISTs (n=319) and 84.5% of the leiomyomas (n=84.5%) were located in the upper third of the stomach. Wedge resection (n=726, 82.8%) was the most common operative method, and laparoscopic surgery was performed in 388 patients (44.2%). Only one patient (0.1%) died within 30 days of surgery. A total of 115 patients withGISTs (21.1%, 115/544) had a high risk of malignancy and 41 patients (8.3%, 45/495) received adjuvant imatinib mesylate therapy. Conclusion: The survey showed that about two-thirds of the patients with a gastric submuscoal tumor (SMT) had a GIST, and about one-half of the patients underwent laparoscopic resection. These data presented in the nationwide survey could be used as a fundamental resource for gastric submucosal tumors in Korea.

• Journal of the Economic Geographical Society of Korea
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• v.9 no.3
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• pp.318-340
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• 2006

In the last decade, there has been a widespread interest in knowledge production activities as a new engine of endogeneous growth. In the knowledge-based economy, there has been a growing importance of the patent as the index of knowledge production. Much literature suggests that knowledge production activities tend to be spatially concentrated and formed the clusters in the advanced economies. The purpose of this paper is to analyze spatial-temporal patterns of knowledge production activities in Korea based on a data set of patents from 1981-2000. This paper uses spatial statistical methods and GIS to explore the spatial dimensions of knowledge production activities in Korea. Through this research, it was found that knowledge production activities were unevenly distributed. The knowledge production activity measured by patent counts is highly concentrated in a limited number of cities. The top 10 cities accounted for 68.5% of the total number of patents in the period of 1981-2000, suggesting the existence of a strong concentration of knowledge production activities in Korea. The locations of knowledge production activities by themselves represented a strong spatial autocorrelation. The concentration of knowledge production activities in Korea is spatially correlated to the concentration of adjacent neighboring cities. The location of knowledge production activities is not free from a spatial context and spillover of knowledge production activities are heavily bounded within geographic limits, forming a spatial cluster. There appear some quite a large spatial cluster around the seoul metropolitan area.