• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.1
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• pp.13-19
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• 2016

The flow-excited Helmholtz resonance phenomenon was investigated numerically using Reynolds averaged Navier-Stokes approach. The fundamental cause of the Helmholtz resonance phenomenon is known as shedding of a single discrete vortex from orifice edge that travels during one period of the oscillation. In this study, serrated deflector, which is biomimetic design of the owl's feather, is used to split a single vortex into small vortices. Rectangular deflector and serrated deflector are compared with numerical results of pressure and streamline inside the cavity. Consequently, the serration breaks the shedding period of vortex core and eliminates the resonance. Also, it changes the flow pattern in according to the location of different serration height. By making inflows and outflows occur simultaneously in spanwise direction in the cavity, the period of Helmholtz resonance disappears. Comparing between rectangular deflector and serrated deflector, the serrated deflector can deal with the Helmholtz resonance more effectively.

• Korean Journal of Microbiology
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• v.35 no.3
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• pp.185-191
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• 1999

This study was conducted to investigate the vibrio flora in an edible shellfish. sunset shelfish. Soletelliim olivacen. which were collected in the estuarine area. Dadaepo near Nakdong River in Korea lkoin January 1997 to November 1997. Including five pathogemc vibrios (Vibrio alginolyticus, Vibrio pamhaemol~~licz~s, Vibrio cholerae non-01. Vibrio vulnificus, and Vihrio jl~~vinlis), a lotal of eight species of vlbr~os (Vi61-io splendidrrs biovar I, Vibrio splendidus biovar 11, Vibrio snlrnonicida and Vibrio tr,~biasllii) were identified from the sunset shellfish by heir biochemical characters. The isolation of Vihrio pamhaemolyricns, which is known not to grow below $15^{\circ}C$, in winter season indicates that the sunset shelllish is one oT the natural owl.- wintering hosts for Vibrio parahuemolyticus.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10b
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• pp.284-288
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• 2006

본 논문은 시맨틱 웹 기술이 융합된 지식기반 정보유통 플랫폼(OntoFrame-K$^{(R)}$)의 추론 서비스 시스템 (OntoThink-K$^{(R)}$)에서 이용되는 Persistent Model인 DBMS기반의 온톨로지 확장 모델에 대해 설명하고자 한다. OntoFrame-K$^{(R)}$는 대용량의 지식 데이터를 다루기 때문에 기존에 개발된 온톨로지 추론 엔진을 이용할 경우 많은 한계점을 가지게 된다. 따라서 우리는 대용량의 지식 데이터를 안정적으로 처리할 수 있으며 추론의 신뢰성과 정합성을 가지는 온톨로지 확장 모델을 설계, 구현하였다. 본 모듈은 OWL과 인스턴스 데이터를 트리플 형태로 변환하여 입력 받은 후, 온톨로지 스키마 규칙과 사용자 정의 규칙을 이용한 정방향 추론 방법으로 추론 서비스에서 필요한 지식데이터들을 생성하는 역할을 한다. 본 모델은 DBMS를 이용하여 대용량의 지식 데이터를 저장할 수 있으며, 추론 규칙에 따른 정방향 추론을 통해 지식 모델을 확장하기 때문에 데이터의 정합성이 보장된다.

• Steel and Composite Structures
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• v.21 no.2
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• pp.249-266
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• 2016

The interest of this article lies in the proposition of using bionic method to develop a new sound absorber and analyze the efficient of this absorber in a ski cabin. Inspired by the coupling absorption structure of the skin and feather of a typical silent flying bird - owl, a bionic coupling multi-layer structure model is developed, which is composed of a micro-silt plate, porous fibrous material and a flexible micro-perforated membrane backed with airspace. The finite element simulation method with ACTRAN is applied to calculate the acoustic performance of the multi-layer absorber, the vibration modal of the ski cabin and the sound pressure level (SPL) near the skier's ears before and after pasting the absorber at the flour carpet and seats in the cabin. As expected, the SPL near the ears was significantly reduced after adding sound-absorbing material. Among them, the model 2 and model 5 showed the best sound absorption efficiency and the SPL almost reduced 5 dB. Moreover, it was most effctive for the SPL reduction with full admittance configuration at both the carpet and the seats, and the carpet contribution seems to be predominant.

• Journal of Astronomy and Space Sciences
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• v.32 no.3
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• pp.201-207
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• 2015

An algorithm to automatically extract coordinate and time information from optical observation data of geostationary orbit satellites (GEO satellites) or geosynchronous orbit satellites (GOS satellites) is developed. The optical wide-field patrol system is capable of automatic observation using a pre-arranged schedule. Therefore, if this type of automatic analysis algorithm is available, daily unmanned monitoring of GEO satellites can be possible. For data acquisition for development, the COMS1 satellite was observed with 1-s exposure time and 1-m interval. The images were grouped and processed in terms of "action", and each action was composed of six or nine successive images. First, a reference image with the best quality in one action was selected. Next, the rest of the images in the action were geometrically transformed to fit in the horizontal coordinate system (expressed in azimuthal angle and elevation) of the reference image. Then, these images were median-combined to retain only the possible non-moving GEO candidates. By reverting the coordinate transformation of the positions of these GEO satellite candidates, the final coordinates could be calculated.

• Journal of Astronomy and Space Sciences
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• v.34 no.4
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• pp.303-314
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• 2017

With increased human activity in space, the risk of re-entry and collision between space objects is constantly increasing. Hence, the need for space situational awareness (SSA) programs has been acknowledged by many experienced space agencies. Optical and radar sensors, which enable the surveillance and tracking of space objects, are the most important technical components of SSA systems. In particular, combinations of radar systems and optical sensor networks play an outstanding role in SSA programs. At present, Korea operates the optical wide field patrol network (OWL-Net), the only optical system for tracking space objects. However, due to their dependence on weather conditions and observation time, it is not reasonable to use optical systems alone for SSA initiatives, as they have limited operational availability. Therefore, the strategies for developing radar systems should be considered for an efficient SSA system using currently available technology. The purpose of this paper is to analyze the performance of a radar system in detecting and tracking space objects. With the radar system investigated, the minimum sensitivity is defined as detection of a $1-m^2$ radar cross section (RCS) at an altitude of 2,000 km, with operating frequencies in the L, S, C, X or Ku-band. The results of power budget analysis showed that the maximum detection range of 2,000 km, which includes the low earth orbit (LEO) environment, can be achieved with a transmission power of 900 kW, transmit and receive antenna gains of 40 dB and 43 dB, respectively, a pulse width of 2 ms, and a signal processing gain of 13.3 dB, at a frequency of 1.3 GHz. We defined the key parameters of the radar following a performance analysis of the system. This research can thus provide guidelines for the conceptual design of radar systems for national SSA initiatives.

• Journal of Intelligence and Information Systems
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• v.12 no.2
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• pp.49-65
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• 2006

In this research, we are suggesting intelligent information system fur traveling which is focusing on product bundling and integration of information from various resources on ubiquitous computing environment. It is necessary for products structure to easily integrate according to customers' requirements because traveling product is integrated by various traveling resources like airline, hotel reservation, and so on. To guarantee of traveler's mobility in ubiquitous computing environment, we need product bundling and modification process to configure products and semantic web service which supports ontology based traveling information system to support immediate integrating of traveling information from various resources. In this research, we offer a product bundling and integration of information. It is based on the semantic web service, with several components (single products) to reconfigure a bundle of traveling products.

• The KIPS Transactions:PartB
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• v.14B no.3 s.113
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• pp.199-214
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• 2007

Recently, there have been a lot of works trying to realize automated composition of semantic web services though application of AI planning techniques. The traditional AI planning techniques, however, have some limitations: it is not easy to represent a web service process with complex control constructs as an action or a plan; it is hardly possible to consider enough the rich information contained in domain ontologies during the planning process; it is impossible to model directly the data flow from the outputs of a web service to the inputs of another web service; it is difficult to predict and deal with uncertainty and dynamics of the environment because the plan generation phase is supposed to be separated from the plan execution phase. In order to overcome some of these limitations, this paper suggests a reactive planning approach to automated composition of semantic web services. Through some experiments using several e-commerce web services, we found that the reactive planning is an effective way to realize automated composition of semantic web services.

• Journal of Korea Multimedia Society
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• v.10 no.2
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• pp.147-169
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• 2007

Semantic Web Services Discovery matches between users' requirements and the ontological description of Web Services. However, concepts of an ontology can be interpreted differently according to a point of view. Previous works are limited in interpreting concepts. Since they lack a precise scheme of describing the advertisements and requirements of services and users, respectively, and even do not support a sophisticated matching, semantic mismatches may occur. This paper presents a sophisticated method of discovering Web services. The proposed method facilitates specifying semantics precisely and flexibly based on a proposed integrated concept model. Additionally, more sophisticated discovery is supported by computing complex matchings with many-to-many relationships. Experimental results show that the proposed method performs more efficiently for various kinds of user requests, compared with previous works.

• Journal of Korean Classical Literature and Education
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• no.15
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• pp.355-387
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• 2008

The purpose of the study was to decide Korean translation and the copying period of "Korean Translation of " and to look all around their characteristics in different versions carefully until now. The "Korean Translation" is a collection of Korean-translated romance and love stories excavated by a professor Kim,Il Geun, and there is not a little meaning in the context of novel history in the point of view of 'Korean translation of a court possession'. Arranging conclusion of the study generally, it is as follows. (1) Considering phonological phenomena, grammar and vocabulary in the study of Korean language, it is presumed that they would be translated into Korean and copied between the regime period of the King Sukjong and the regime period of the King Yungjo in the Joseon Dynasty. For, they were composed of a middle declaration of copied 'Myeoknambon "Korean Translation of Taepyeonggwanggi(태평광기)"' and 'NakseonJaebon(낙선재본)' between the middle of the 17th century and the middle of the 18th century and the regime period of the King Jeongjo in the Joseon Dynasty appointed as the background period of the novels should be excepted. Consequently, through the Korean Translation, we can confirm that the novel scope between the 17th century and the 18th century in Korean novel history was widened until 'The Royal Court' and 'Women'. (2) In the side of vocabulary, the "Korean Translation" also has not a little meaning in the side of a collection translated in the Royal Court. It doesn't have new vocabularies, but partial vocabularies as '(Traces:痕)' '(Clean eyes:明眸)', ' (Sail:帆)', '(Get up:起)', '글이플(Weak grass:弱草)', '쇼록(Owl:? 梟 or 鴉?)', '이 사라심(This life:此生)', and '노혀오매(Look for:訪)' are good data in the study of Korean language. (3) The "Korean Translation" is a valuable data about translation and copying of a court novel and we can discover intentionally changed parts and partially omitted sentences rather in the than in the . There are differences between a translation book and a copying book and we can catch sight of intention of translation and unsettledness of copying in the second work. Therefore, we can know that the "Korean Translation" has a double context which one work is translated and a work in different version is derived, compared to a simple copy. (4) The "Korean Translation" has a close relation with "Hangoldong(閒汨董)", but it doesn't regard the same copy as a foundation. The basic copy of translation of the "Korean Translation" is a different version of the same line as "Hangoldong" and "Jeochobon(저초본:정명기 소장본)" and is more similar line to "Hangoldong", but it is also not the same basic copy. (5) Considering that the "Korean Translation" doesn't has a distinct relation with the "Hangoldong", there is no correlation between the "Korean Translation" and and the "Hangoldong" and . In addition, we could not discover a writer's identity between the two.