• 인터넷정보학회논문지
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• 제18권1호
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• pp.77-88
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• 2017

최근 지식과 정보가 가치를 생산하는 지식기반사회로 접어들면서 지식재산권의 대표적인 형태인 특허에 대한 중요성이 매우 높아지고 있으며 출원되는 특허의 양도 매년 증가하고 있다. 방대한 양의 특허정보를 효과적으로 이용하기 위해서 특허문서를 그 발명의 기술적 주제에 따라 적절하게 분류하는 것이 필요하며 이를 위해 IPC(International Patent Classification)가 주로 사용되고 있다. 현재 주로 사람의 손으로 이뤄지는 특허문서의 IPC 분류과정의 효율성을 높이기 위하여 다양한 데이터마이닝과 기계학습 알고리즘을 기반으로 IPC 자동분류에 관한 연구들이 수행되어 왔다. 하지만 기존의 IPC 자동분류에 관한 연구의 대부분은 특허문서의 구조적 특징과 같은 특허문서 고유의 데이터 특성에 대한 고려보다는 다양한 기계학습 알고리즘을 특허문서로 적용하는 것에 초점을 맞춰왔다. 이에 본 논문에서는 IPC 자동분류를 위해 특허문서의 특징과 구조적 필드의 역할을 기반으로 특허문서 분류에 영향을 끼치는 두 가지 필드, 기술분야 및 배경기술 필드의 활용을 제안한다. 그리고 특허문서가 동시에 다수의 IPC 분류코드를 가지는 점을 반영하여 다중 레이블 분류(multi-label classification) 모델을 구축한다. 또한 IPC 다중 레이블 분류의 실제 현장에서의 적용 가능성 확인을 위해 630개의 범주를 가지는 IPC 서브클래스 레벨까지 분류 가능한 수법을 제안한다. 이를 위해 국내에서 등록된 564,793건의 특허문서를 대상으로 특허문서의 구조적 필드의 영향을 확인하기 위한 IPC 다중 레이블 분류 실험을 수행하였고, 그 결과 제목, 요약, 청구항, 기술분야 및 배경기술 필드를 활용한 실험에서 87.2%의 싱글매치 정확도를 얻었다. 이를 통해 기술분야 및 배경기술 두 필드가 IPC 서브클래스 레벨까지의 다중 레이블 분류의 정확도를 향상시키는데 중요한 역할을 하고 있음을 확인하였다.

• 한국해양학회지:바다
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• 제6권2호
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• pp.81-92
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• 2001

황해 중동부 해역 ($36^{\circ}00'N{\sim}36^{\circ}45'N$,$\;125^{\circ}00'E{\sim}125^{\circ}45'E$)에 분포하는 퇴적층을 대상으로 획득한 고해상 탄성파탐사자료(에어건, 스파커, SBP)와 심부 시추시료(YSDP 105, ${\sim}$64m 깊이)의 종합분석에 따라, 연구 해역의 층서모델을 설정하고 탄성 -음향 모델링을 수행하였다. 층서모델은 탄성파${\cdot}$암${\cdot}$시 층서 단위들을 비교 분석하여 각 지층단위의 음향학적 특성, 퇴적과정, 생성시기를 규명하였다 또한 단위층 형성과정을 해수면 변동과 관련지어 순차층서를 복원하였다. 각 순차층은 육성 또는 천해성 기원이며 조립질의 저해수면 퇴적계와 조석 기원 세립질의 해침-고해수면 퇴적계로 구성되어 있다. 탄성-음향 모델링의 매개변수 산출을 위해, 0.S~90 cm 심도 간격으로 측정된 시추코아의 121 개 평균입도 자료를, Hamilton의 회귀식과 퇴적심도에 따른 변화구배를 이용하여, 전밀도(bulk density)값과 종파속도값으로 변환${\cdot}$계산하였다. 외삽${\cdot}$보정된 121 쌍의 전밀도${\cdot}$종파속도 물성값은 설정된 층서모델에서 제시된 단위층 별로 평균하여 각 단위층의 대표값으로 산출하였다. 퇴적층 내의 탄성-음향 전파 모델링을 위해, 층서모델의 각 단위층에 전밀도와 종파속도의 대표값을 입력 매개변수값으로 부여한 후, 층서 구성 단위층들을 유한요소격자로 분해하였다. 파선추적법의 컴퓨터 모델링 결과, 탄성-음향의 전파는 층서모델을 구성하는 단위층 경계면의 불규칙성과 저속도층의 다수 존재에 의하여 매우 복잡한 음경로를 보이며, 음원의 위치에 따라 탄성-음파의 암영대가 달리 존재함을 확인하였다. 것으로 보아 층 2는 고에너지환경에서 형성되었음을 시사한다. 또한 층 2에서 Al의 증가는 쇄설기원 물질의 유입에 의한 것으로 추정된다. 플라이오세 이후에 형성된 층 1은 치밀한 조직을 보이며, 형성 이후 속성작용을 받지 않았다.선택적으로 분해되는 것으로 여겨진다.두냔 tsuchigae, S. nigripinni morii, M. jeoni, C. splendidus, P. koreanus, C. lutheri, I. koreensis, C. herzi, R. brunneus 등으로 본 종들의 서식 상태는 하천의 오염 정도 및 하천개수와 직접적인 관계가 있으므로 어류서식 환경을 유지시키기 위해서 보다 적극적인 하천 수질관리의 대책과 방안이 수립되어야 될 것으로 사료된다.와 운동, H-R도상에서의 별의 특성과 진화 등이다. 탐구 과정에 대한 학생의 성취도는 비교적 높으므로 이해도가 상대적으로 낮은 영역에 대해 학생의 오답 유형을 참고하여 기본 개념 지도에 보다 관심을 기울일 필요가 있다.Cr은 FW에서 전반적으로 감소하는 경향을 보였지만 SW에서는 실험 초기에 감소하다 24시간 이후에는 증가 후 일정한 양상을 보였다. Pb은 FW에서 전반적으로 감소했지만 SW에서는 초기에 급격히 증가 후 다시 급격히 감소하는 양상을 보였다 Pb 또한 Cu, Cd, As와 마찬가지로 SW1&2에서 제거속도가 가장 빠르게 나타났다. FW 상층수 중 Hg는 시간에 따라 급격히 감소했고, 제거속도는 Fw5&6에서 가장 느렸다. 이러한 결과에 근거할 때 벼가 자라고 있고 이분해성 유기물이 풍부한 FW1&2, FW3&4 토양과 상층수에서는 유기물의 분해 활동이 활발하였지만, 벼가 경작되지 않는 FW5&6과 SW 에서는 유기물이 상대적으로 결핍되어 유기물의 분해활동이 적었을 것으로 판단된다. 한편, 수조에 인위적으로 유기물을 첨가한 경우 박테리아 세포수는 SW1에서 164시간 동안 4배 증가하였으나 SW3과 SW5에서는 각각 2.7배, 1.

• 한국문헌정보학회지
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• 제15권
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• pp.225-266
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• 1988

Various theories and techniques for the subject catalog have been developed since Charles Ammi Cutter first tried to formulate rules for the construction of subject headings in 1876. However, they do not seem to be appropriate to Korean language because the syntax and semantics of Korean language are different from those of English and other European languages. This study therefore attempts to develop a new Korean subject indexing system, namely Korean String Indexing System(KOSIS), in order to increase the use of subject catalogs. For this purpose, advantages and disadvantages between the classed subject catalog nd the alphabetical subject catalog, which are typical subject ca-alogs in libraries, are investigated, and most of remarkable subject indexing systems, in particular the PRECIS developed by the British National Bibliography, are reviewed and analysed. KOSIS is a string indexing based on purely the syntax and semantics of Korean language, even though considerable principles of PRECIS are applied to it. The outlines of KOSIS are as follows: 1) KOSIS is based on the fundamentals of natural language and an ingenious conjunction of human indexing skills and computer capabilities. 2) KOSIS is. 3 string indexing based on the 'principle of context-dependency.' A string of terms organized accoding to his principle shows remarkable affinity with certain patterns of words in ordinary discourse. From that point onward, natural language rather than classificatory terms become the basic model for indexing schemes. 3) KOSIS uses 24 role operators. One or more operators should be allocated to the index string, which is organized manually by the indexer's intellectual work, in order to establish the most explicit syntactic relationship of index terms. 4) Traditionally, a single -line entry format is used in which a subject heading or index entry is presented as a single sequence of words, consisting of the entry terms, plus, in some cases, an extra qualifying term or phrase. But KOSIS employs a two-line entry format which contains three basic positions for the production of index entries. The 'lead' serves as the user's access point, the 'display' contains those terms which are themselves context dependent on the lead, 'qualifier' sets the lead term into its wider context. 5) Each of the KOSIS entries is co-extensive with the initial subject statement prepared by the indexer, since it displays all the subject specificities. Compound terms are always presented in their natural language order. Inverted headings are not produced in KOSIS. Consequently, the precision ratio of information retrieval can be increased. 6) KOSIS uses 5 relational codes for the system of references among semantically related terms. Semantically related terms are handled by a different set of routines, leading to the production of 'See' and 'See also' references. 7) KOSIS was riginally developed for a classified catalog system which requires a subject index, that is an index -which 'trans-lates' subject index, that is, an index which 'translates' subjects expressed in natural language into the appropriate classification numbers. However, KOSIS can also be us d for a dictionary catalog system. Accordingly, KOSIS strings can be manipulated to produce either appropriate subject indexes for a classified catalog system, or acceptable subject headings for a dictionary catalog system. 8) KOSIS is able to maintain a constistency of index entries and cross references by means of a routine identification of the established index strings and reference system. For this purpose, an individual Subject Indicator Number and Reference Indicator Number is allocated to each new index strings and new index terms, respectively. can produce all the index entries, cross references, and authority cards by means of either manual or mechanical methods. Thus, detailed algorithms for the machine-production of various outputs are provided for the institutions which can use computer facilities.

• 아동학회지
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• 제1권
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• pp.65-81
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• 1980

This study is aimed at investigating the compensatory education which was already implemented or is being implemented in the U.S.A. and Japan; and at studying the types of programs and their characteristics; and at sounding out the possibilities of the application of such programs in family and social conditions is Korea. In order to achieve the above mentioned objectives, the established items for the study are as follows: (1) Various types of early children's education (2) Programs of compensatory education for the disadvantaged Children (3) Head Start Program, Early Training Project and Montessori School (4) Integrated Preschool Programs (5) Day-Care Center for employed mothers We investigated the various compensatory education programs for the preschool children who are in economically, socially, culturally disadvantaged conditions. Head Start Programs were federally supported programs for preschool children and opened as summer programs in 1965 for the first time. The purpose of Head Start has been to give preschool children the kinds of experiences they need in preparation for school. The Head Start children were found to be significantly better prepared for school than the normal children. However, after six to eight months, their initial advantages had virtually. disappeared and then the simple problem with Head Start and other such programs was that little long-term good could be evidenced unless the high quality educational environment was maintained. Therefore, to solve this problem, three other programs were funded as part of the overall Head Start. These three programs are the Parent-Child Center, Home Start, and the Child and Family Resources Program. The Early Training Project for disadvantaged children was implemented by Klaus and Gray of Peabody College in 1962. The program was a field research study concerned with the development and testing over time of procedures for improving the educability of young children from low income homes. Its major concern was to study whether it was possible to offset the progressive retardation observed in the public schooling careers of children, living in deprived circumstances. Children, who were trained through the Early Training Project were superior to control groups in the test of IQ and vocabulary as well as linguistic abilities, and preparation for reading. This project showed the possibilities which could prevent preschool children from being disadvantaged socially, culturally and mentally. In 1907, Montessori School was established by Maria Montessori in Italy and her school program has been introduced at present to several countries in the world as one compensatory educations. She first began her experimental methods with retarded children, followed by disadvantaged children from the tenements of Rome. The Montessori approach futures a prepared environment and carefully designed, self-correcting materials. The Montessori curriculum presents tastes that feature sequence, order, and regularity, in addition to those that develop motor and sensory skills. She was interested in children's intellectual development and in developing good work habits. One of the latest developed programs for disadvantaged children is "Integrated Preschool Program" which has successfully integrated handicapped and nonhandicapped children. Several studies have showed that handicapped children in integrated school environments are accepted by and interact with their nonhandicapped peers. In fact, this program provides a number of potential, and perhaps opportunities for nonhandicapped children to serve as valuable resources in fostering the development of their handicapped peers. Next we turn to Japanese programs which are divided into two different types. One is Day-Care Center which was established by Child Welfare Law and the other is kindergarten organized by School Education Law. The kindergarten opened in 1876 and it has been part of school systems since 1947 by the implementation of education law, and the Day-Care Center which started in 1890 for the employed mothers. was changed into Day-Nursery by the enactment of child welfare law in 1947. The laws and operational regulations for the Day-Nursery were set up and were put in effect by the establishment standard acts of children welfare facilities, and the Day-Nursery has been operated in various types by the increasing demand, chiefly because of the socio-economical changes of family structures in both urban and suburban areas. Nursery education for physically and mentally disadvantaged children is for those who are blind, deaf and dumb, mentally retarded; physically disadvantaged by accidents or diseases. Montessori education in Japan was started in 1968 and many research groups for studying Montessori were organized. In 1977, Montessori remedial education society was also organized in which they started a number of studies; a study for developing materials; in-service training for the remedial education; and seminars and lectures, etc It is strongly suggested that we study the early educations that are being implemented in Japan and a variety of compensatory educations that were already implemented in the U.S.A. and modify them for the organization of our own model and properly accommodate them to our social needs.

• Investigative Magnetic Resonance Imaging
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• 제8권1호
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• pp.32-41
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• 2004

목적 : MnPC의 자기이완성질을 살펴보고, 토끼의 간에 이식한 VX2 암종을 이용해 자기공명영상에서 간의 조영증강형태를 관찰하고자하였다. 또한 간세포 특이성 조영제 사용 시와 비교하여 MnPC의 조직특이성 조영제로서의 가능성을 탐색해 보고자 하였다. 대상 및 방법 : 조영제 합성시 상자성 원소의 배위자로 phthalocyanine(PC)를 선택하였다. 2.01 g (5.2 mmol)의 phthalocyanine을 0.37g(1.4 mmol)의 manganese chloride와 $310^{\circ}C$에서 36시간동안 반응시킨 후 혼합물을 크로마토그래피 (CHC13: CH3OH=98:2, volume ratio)로 정제하여 2000 달톤의 분자량을 갖는 1.04 g $(46\%)$의 MnPC를 얻었다. 자기이완율은 MnPC를 0.1 mmol로 희석시켜 1.5 T (64 MHz)에서 측정하였다. VX2 암종은 토끼의 간실질 내에 종양세포 부유액을 주입해 실험적으로 유발시켰다. 모든 영상은 1.5 T MR장비에서 무릎관절코일을 사용하여 획득하였다. 본 연구에서 새로 개발된 거대분자 자기공명영상 조영제인 MnPC (4m-mol/kg)와 간세포 특이성 조영제인 Mn-DPDP (0.01 mmol/kg)가 사용되었으며 이들 조영제는 토끼의 이정맥을 통해 주입되었다. T1 강조영상은 스핀에코 (TR/TE=516/14 msec)와 고속다면회손경사회복 (TR/TE=80/4 m-sec, flip angle $60^{\circ}$)을 사용하여 얻었고, T2 강조영상의 획득을 위해서는 고속스핀에코 (TR/TE=1200/85 m-sec)를 사용하였다. 결과 MnPC의 1.5T (64MHz)에서의 자기이완율은 $R1=7.28\;mM^{-1}S^{-1}$, $R2=55.56\;mM^{-1}S^{-1}$ 이었고, MnPC의 높은 T2 자기이완율은 T2 강조영상에서의 정상 간실질의 신호강도를 감소시켜 간실질과 VX2 암종의 구분을 쉽게 하였다. MnPC 주입시 T1 강조영상에서는 간세포 특이성 조영제의 주입시보다 종양의 경계가 명확하였고, 조영증강은 주입후 최소한시간 이상 높게 유지되었다. 결론 : MnPC가 간세포로 흡수되어 담관으로 배설된다는 사실은 Mn-DPDP와 유사한 특성이며 이는 MnPC가 새로운 간특이성 조영제임을 확인시켜 준다. 또한 MnPC의 R2값이 기존의 조영제에 비해 매우 크다는 사실은 T1 조영제로서 뿐만 아니라 T2 조영제로서의 사용 가능성을 보여준다. 이러한 사실들을 좀더 정확하게 뒷받침하기 위해서는 임상적으로 사용되기 이전에 생체 내 그리고 시험관내 연구가 더 필요하며 다른 동물모델에서의 추가적인 연구가 요구된다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 1998년도 가을 학술발표회 프로그램
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• pp.2-4
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• 1998

Proliferation of Nocardia amarae cells in activated sludge has often been associated with the generation of nuisance foams. Despite intense research activities in recent years to examine the causes and control of Nocardia foaming in activated sludge, the foaming continued to persist throughout the activated sludge treatment plants in United States. In addition to causing various operational problems to treatment processes, the presence of Nocardia may have secondary effects on the fate of heavy metals that are not well known. For example, for treatment plants facing more stringent metal removal requirements, potential metal removal by Nocardia cells in foaming activated sludge would be a welcome secondary effect. In contrast, with new viosolid disposal regulations in place (Code o( Federal Regulation No. 503), higher concentration of metals in biosolids from foaming activated sludge could create management problems. The goal of this research was to investigate the metal sorption property of Nocardia amarae cells grown in batch reactors and in chemostat reactors. Specific surface area and metal sorption characteristics of N. amarae cells harvested at various growth stages were compared. Three metals examined in this study were copper, cadmium and nickel. Nocardia amarae strain (SRWTP isolate) used in this study was obtained from the University of California at Berkeley. The pure culture was grown in 4L batch reactor containing mineral salt medium with sodium acetate as the sole carbon source. In order to quantify the sorption of heavy metal ions to N amarae cell surfaces, cells from the batch reactor were harvested, washed, and suspended in 30mL centrifuge tubes. Metal sorption studies were conducted at pH 7.0 and ionlc strength of 10-2M. The sorption Isotherm showed that the cells harvested from the stationary and endogenous growth phase exhibited significantly higher metal sorption capacity than the cells from the exponential phase. The sequence of preferential uptake of metals by N. amarae cells was Cu>Cd>Ni. The specific surFace area of Nocardia cells was determined by a dye adsorption method. N.amarae cells growing at ewponential phase had significantly less specific surface area than that of stationary phase, indicating that the lower metal sorption capacity of Nocardia cells growing at exponential phase may be due to the lower specific surface area. The growth conditions of Nocardia cells in continuous culture affect their cell surface properties, thereby governing the adsorption capacity of heavy metal. The comparison of dye sorption isotherms for Nocardia cells growing at various growth rates revealed that the cell surface area increased with increasing sludge age, indicating that the cell surface area is highly dependent on the steady-state growth rate. The highest specific surface area of 199m21g was obtained from N.amarae cell harvested at 0.33 day-1 of growth rate. This result suggests that growth condition not only alters the structure of Nocardia cell wall but also affects the surface area, thus yielding more binding sites of metal removal. After reaching the steady-state condition at dilution rate, metal adsorption isotherms were used to determine the equilibrium distributions of metals between aqueous and Nocardia cell surfaces. The metal sorption capacity of Nocardia biomass harvested from 0.33 day-1 of growth rate was significantly higher than that of cells harvested from 0.5- and 1-day-1 operation, indicatng that N.amarae cells with a lower growth rate have higher sorpion capacity. This result was in close agreement with the trend observed from the batch study. To evaluate the effect of Nocardia cells on the metal binding capacity of activated sludge, specific surface area and metal sorption capacity of the mixture of Nocardia pure cultures and activated sludge biomass were determined by a series of batch experiments. The higher levels of Nocardia cells in the Nocardia-activated sludge samples resulted in the higher specific surface area, explaining the higher metal sorption sites by the mixed luquor samples containing greater amounts on Nocardia cells. The effect of Nocardia cells on the metal sorption capacity of activated sludge was evaluated by spiking an activated sludge sample with various amounts of pre culture Nocardia cells. The results of the Langmuir isotherm model fitted to the metal sorption by various mixtures of Nocardia and activated sludge indicated that the mixture containing higher Nocardia levels had higher metal adsorption capacity than the mixture containing lower Nocardia levels. At Nocardia levels above 100mg/g VSS, the metal sorption capacity of activate sludge increased proportionally with the amount of Noeardia cells present in the mixed liquor, indicating that the presence of Nocardia may increase the viosorption capacity of activated sludge.

• 동서간호학연구지
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• 제10권1호
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• pp.11-26
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• 2004

The purpose of this study is to investigate the present conditions of nursing investment contents, its conversion process, and output in Oriental University Medical Center, Korea to get good qualified Oriental nursing result which is the ultimate purpose of the Oriental nursing management, and to develope a matrix of Oriental nursing management system on the basis of that project. The subjects for nursing investment and output contents were eighteen nursing directors in eleven Oriental University Medical Center and two hundred thirty-nine nurses with three years and over experience in Oriental medical center. The subjects for Oriental nursing organization, human affair management, and control function were nineteen Oriental medical center in Oriental University Medical Center, Korea. Data were collected from November, 2002 to February, 2003 with questionnaire. Data analysis was done by SPSS PC+ 12 program. Frequency, percentage, and minimum/maximum values were used for investment contents, and frequency and percentage were used for conversion process and output contents. 1. The input factors of oriental nursing management system The objective's western hospital career was over five years of one hundred and seventy-five(73.2%) persons. Nursing in-service education was performed in fourteen hospitals(77.8%). Two hundreds(83.7%) were pro to oriental nurse system. Only four hospitals(22.2%) had independent budget in nursing division. Nursing staff allocation to the bed was from 2.8:1 to 9.06:1 respectively, with a big gap of the rate following the hospitals. 2. The conversion factors of oriental nursing system 1) Oriental nursing system Oriental hospital nursing system was organized independently in ten hospitals among eighteen hospitals. The recruitment of nurses which was a vital role of the nursing division of the hospital was mostly(79%) opened. The education to develope nursing personnels was through in-service one in 97.4%. Education for oriental nursing and management was performed in 42.1%(eight hospitals) and that for reserves was done in 36.8%(seven hospitals). Administration for nursing education by nursing division was 68.5%(thirteen hospitals). The post education evaluation was performed by report submission in 36.8%(seven hospitals), by written examination in 26.3%, by questionnaires in 21.1%, and by lecture presentation in 15.8% subsequently. The directorial meeting for the nursing directors was attended by 84.2%(sixteen hospitals), and the meeting type was the medical executive and support division executive meeting in 55.6%(ten hospitals) and the personnel management in 39.6%(seven hospitals). 2) The actual conditions of oriental nursing personnel management The reason of working in oriental hospital was by voluntary in 67.1%(a hundred and sixty persons), by nursing department order in 28.0%(sixty-seven persons), and by others in 5.0%(twelve persons) respectively. The shift form was a three-shifts one in 94.7%(eighteen hospitals), a two-shift one in only one hospital. Duty assignment was functional in 52.6%(ten hospitals), team and functional in 26.3%(five hospitals) and no team alone. Promotion manual was present at 68.4%(thirteen hospitals) and the competency essentials comprised of performance evaluation in 79%, interview, written examination, training result, study result subsequently. No labor union existed in 79%(fifteen hospitals) 3) Oriental nursing preceptor system There were five oriental hospitals(27.7%) administering the preceptor utilization model, which showed lower rate than the twenty-two medical university hospitals in Seoul in which fifteen hospitals (72.7%) were having the system. To the question of necessity of oriental nurse system asked to the objectives of two hundred and thirty-nine with more than three year-experience in oriental hospital, two hundred persons(83.7%) answered positively. 4) The control of oriental nursing The evaluation results from the target hospitals were mostly not opened in 89.4% of oriental hospitals. Thirteen hospitals(68.3%) had evaluation system of direct managers and the next were three hospitals(15.8%) of direct managers and selves. There was one hospital(5.3% each) where fellows and superiors, fellows, and inferiors' evaluation was performed and no hospital where superiors, fellows, inferiors and selves, and superiors, fellows and selves' evaluation was performed. The QI activity of nursing was 42.1%(eight hospitals) for nursing service evaluation, 36.8% for survey of ECSI, 26.3% for survey of ICSI, 15.8% for medical visit rate, 10% for hospital standardization inspection in sequence. 3. The output factors of oriental nursing management system The job satisfaction appeared good in general, indicating very good in thirty-seven persons (15.7%), good in one hundred and fourteen persons (48.3%) and fair in eighty-five persons(36.0%).

• 지능정보연구
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• 제26권2호
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• pp.43-56
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• 2020

추천 시스템은 사용자가 다양한 옵션 중에서 최선의 선택을 할 수 있도록 도와준다. 그러나 추천 시스템이 상업적으로 성공하기 위해서는 극복할 몇 개의 문제점이 존재한다. 첫째, 추천시스템의 투명성 부족 문제이다. 즉, 추천된 상품이 왜 추천되었는지 사용자들이 알 수 없다. 둘째, 추천시스템이 사용자 선호의 변화를 즉각적으로 반영할 수 없는 문제이다. 즉, 사용자의 상품에 대한 선호는 시간이 지남에 따라 변함에도 불구하고, 추천시스템이 사용자 선호를 반영하기 위해서는 다시 모델을 재구축해야 한다. 따라서 본연구에서는 이러한 문제를 해결하기 위해 토픽 모델링과 순차 연관 규칙을 이용한 추천 방법론을 제안하였다. 토픽 모델링은 사용자에게 아이템이 왜 추천되었는지 설명하는데 유용하며, 순차 연관 규칙은 변화하는 사용자의 선호를 파악하는데 유용하다. 본 연구에서 제안한 방법은 크게 토픽 모델링 및 사용자 프로파일 생성 등 토픽 모델링에 기반한 사용자 프로파일 생성 단계와 토픽에 사용자 선호 확인 및 순차 연관 규칙 발견 등 순차 연관 규칙에 기반한 추천 단계로 구분된다. 벤치마크 시스템으로 협업 필터링 기반 추천 시스템을 개발하고, 아마존의 리뷰 데이터 셋을 이용하여 제안한 방법론의 성능을 비교 평가하였다. 비교 분석 결과, 제안한 방법론이 협업 필터링 기반 추천시스템보다 뛰어난 성능을 보였다. 따라서 본 연구에서 제안하는 추천 방법을 통해 추천 시스템의 투명성을 확보할 수 있을 뿐만 아니라, 시간에 따라 변화하는 사용자의 선호를 반영할 수 있다. 그러나 본 연구는 토픽과 관련된 상품을 추천하기 때문에, 토픽에 포함된 상품의 수가 많을 경우 추천이 정교하지 못하는 한계점이 있다. 또한 토픽의 수가 적기 때문에 토픽에 대한 순차 연관 규칙이 너무 적은 문제점이 있다. 향후 연구에서 이러한 문제점을 해결한다면 좋은 연구가 될 것으로 판단된다.

• 대한치과보철학회지
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• 제59권4호
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• pp.395-404
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• 2021

목적: 본 연구의 목적은 절삭가공이 순차적으로 진행됨에 따른 왁스 디스크의 구조적 안정성의 변화가 보철물의 적합도에 미치는 영향을 평가하는 것이다. 재료 및 방법: 삭제된 상악 제1대구치 인공치아를 이용하여 Ni-Cr 합금 표준모형을 제작하였고, 이를 스캔하여 크라운을 디자인한 뒤 왁스 디스크를 절삭가공하고 매몰 및 Ni-Cr 합금으로 주조하여 보철물을 제작하였다. 단일 왁스 디스크 내에서 중앙에 일렬로 위치한 납형들은 가장 처음 절삭가공 되는 WM1군부터 마지막에 절삭가공 되는 WM5군으로 총 5개의 군을 설정하였고 각 군의 수는 10개로 하였다. 적합도는 실리콘 레플리카 방법을 이용하여 변연 간극, 축면 간극, 선각간극, 교합면 간극을 측정하였다. 측정값은 일원배치분산분석(one-way ANOVA)을 사용하여 유의 수준은 95%로 그룹 간의 차이를 평가한 뒤, 사후 분석을 위해 Tukey HSD test를 시행하였다(α = .05). 결과: 각 군의 변연 간극은 WM1군(40.41 ± 2.15 ㎛), WM2군(40.44 ± 2.23 ㎛), WM3군(39.96 ± 2.25 ㎛), WM4군(39.96 ± 2.48 ㎛), WM5군(40.57 ± 2.53 ㎛)으로 각 군간에 유의한 차이를 보이지 않았다. 축면 간극, 선각 간극, 교합면 간극에서도 각 군간에 유의한 차이를 보이지 않았다. 결론: 단일 절삭가공용 왁스 디스크 내에서 순차적 절삭가공 시 크라운의 내면 및 변연 적합도는 절삭 순서에 영향 받지 않는 것으로 보인다.

• 대한소아치과학회지
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• 제30권2호
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• pp.308-319
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• 2003

기능력은 뼈의 형성, 유지 및 개조 이외에도 치아이동, 교정치료, 기능성 악교정장치의 사용 등과 관련한 치주인대세포의 특성 변화 등에 중요한 영향을 미친다. 또한, 하악과두에서도 기능력의 변화에 따라서 다양한 특성의 변화가 나타난다. 본 연구에서는 ICR 생쥐를 8주 동안 soft-diet와 hard-diet의 식이 조절을 통해 기능력의 변화를 유도하여, 기능력의 변화와 관련한 특이 유전자를 검출하기 위하여 subtractive hybridization, northern 분석 및 mRNA in-situ hybidization 등의 실험을 시행하여 다음과 같은 결과를 얻었다. 1. Soft-diet군과 hard-diet군의 subtractive hybridization을 통하여 총 39개의 clone을 얻었고 이중에서 11개의 서로 다른 hard-diet군 특이 후보 유전자들을 분리하였다. 2. 11개의 후보 유전자들 중에서 homology 검색과 northern 분석을 통하여 기능력과 관련이 있을 것으로 생각되거나 hard-diet군에서 mRNA가 선택적으로 발현되는 FS-s2, FS-s5, FS-s18 및 Fs-s22 유전자를 선택하였다. 3. Soft-diet군과 hard-diet군의 형태학적 분석에서 soft-diet군은 hard-diet군에 비하여 골모세포의 활성과 골개조의 특성은 저하된 것으로 관찰되었으나, 하악과두의 연골성골화 과정은 오랜 시간동안 지속되는 것으로 나타났다. 4. FS-s2, FS-s5, FS-s18 및 Fs-s22 유전자의 cRNA 탐침자를 이용한 in-situ hybridization에서 4개의 유전자의 mRNA들은 hard-diet군의 세포들에서는 강하게 발현되었으나 soft-diet군의 세포들에서는 그 발현이 미약하거나 나타나지 않았다. 이상의 결과를 종합하여 FS-s2, FS-s5, FS-s18 및 Fs-s22 유전자들은 대부분이 기능이 거의 알려져 있지 않는 것들로 기능력의 변화 과정에서 중요한 역할을 할 것으로 생각되나 앞으로 보완 연구를 통하여 각 각의 유전자들의 보다 정확한 기능을 이해하는 것이 필요 할 것으로 사료된다.