• The Journal of Information Technology and Database
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• v.5 no.1
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• pp.13-37
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• 1998

인터넷 등의 컴퓨터 통신 네트워크의 발달로 인하여 분산된 정보자원의 공유를 통한 자원에 대한 재사용성의 필요성이 대두되었다. IRD(Information Resource Dictionary)는 조직 내에서 관련된 모든 정보에 대한 데이터가 논리적으로 중앙화된 정보저장소(repository)이다. IRD 내의 데이터는 다른 데이터를 기술하므로 이른바 메타 데이터라고 하기도 한다. IRD의 사전(dictionary) 요소는 정보자원의 종류, 정보자원의 의미, 정보자원의 논리적 구조, 정보자원의 위치, 그리고 정보자원의 접근방법 등을 기술한다. FIPS ANSI의 IRDS는 이항 관계를 이용하여 무결성 제약조건을 표현하므로 제약조건 규칙의 표현과 일반적인 추론 규칙의 표현이 제한되어 있으며, 다양한 형태의 무결성 제약조건의 표현과 IRD와 관련된 여러 정보의 도출 또는 추론 및 관리에 관한 사항은 IRD 응용 고유의 문제로 간주하여 언급하고 있지 않다. 한편, FIPS IRDS는 사용자가 SQL 및 IRD에 대한 전문적 지식이 없이는 사용자 질의 작성이 어려운 점등에 대한 문제점을 안고 있다. 본 논문은 FIPS IRDS의 기본모델에서 정보자원 표현, 정보자원들간의 관계, 정보자원의 관리 정보 구분을 명확히 하기 위해 정보자원 모델을 정보자원 표현요소와 정보자원 관리요소의 두 부류로 나누어 구분하고, 각 부류에 대한 자격 질의(competency question)를 통하여 유추된 요소들을 FIPS ANSI IRDS 기본 모델의 스키마 기술 레벨과 스키마 레벨에 첨가함으로써 그 기본 모델을 확장한다. 그리고, FIPS ANSI IRDS가 제공하는 IRD 기술과 관리 기능을 그대로 포함하면서 앞에서 문제점으로 지적된 제약조건 표현과 추론규칙 표현을 위하여 확장된 기본 모델을 중심으로 각 레벨의 구성 요소들의 형식적 의미(formal semantics)와 레벨 내 혹은 레벨 구성요소들간의 관계성(relationship), 그리고 제약조건의 표현과 질의 추론 규칙들을 식별하여 FOPL(First Order Predicate Logic)로 표현한다. 또한, 본 논문은 FOPL로 표현된 predicate들과 규칙들을 구현하기 위하여 Prolog로 변환하기 위한 이론적 방법론을 제시하고 정보자원 관리를 위한 기본 함수들과 스키마 진화(schema evolution)를 위한 방법론을 제안한다.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.6
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• pp.15-27
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• 2004

The Seoul Woods Design Competition in 2003 was one of the most remarkable events within the field of landscape architecture in Korea since the Yeo-Ui Do Square Park Design Competition in the mid 1990s. This study examines the overall procedure, evaluations and competition guidelines for the Seoul Forest Park Design Competition and identifies the implications and issues related to Korean landscape architecture. In addition this study analyzes the design concepts, strategies and spatial composition, and programs of five selected design worts including the best awarded work. This study also examines key features and issues from the five selected design works. Finally, this study examines a new trend of landscape design in Korea, which can be observed at the Seoul Forest Park Design Competition. In this study, it is argued that the Seoul Forest Park Design Competition had significant implications for landscape architecture in Korea. Firstly, the Seoul Forest Park Design Competition was the greatest project in Korea in terms of its size. Therefore, it shows us an enhanced status of Korean landscape architecture. Secondly, the Seoul Forest Park Design Competition provided a good opportunity to redefine the concept of 'park' in Korean modern society. Thirdly, through the Seoul Forest Park Design Competition, we can observe a dramatic change and developments in Korean landscape design since the 1990s, as well as the present status of landscape design competitions in Korea. And this study identifies an emphasis of a program in design, an evolution in ecological approach an diminishment in concern of Korean tradition, and a change in design methods and media, which are some aspects of Korean contemporary landscape design observed at the Seoul Forest Park Design Competition.

• The KIPS Transactions:PartB
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• v.12B no.4 s.100
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• pp.429-436
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• 2005

A simple stereo matching algorithm using population-based incremental learning(PBIL) is proposed in this paper to decrease the general problem of genetic algorithms, such as memory consumption and inefficiency of search. PBIL is a variation of genetic algorithms using stochastic search and competitive teaming based on a probability vector. The structure of PBIL is simpler than that of other genetic algorithm families, such as serial and parallel ones, due to the use of a probability vector. The PBIL strategy is simplified and adapted for stereo matching circumstances. Thus, gene pool, chromosome crossover, and gene mutation we removed, while the evolution rule, that fitter chromosomes should have higher survival probabilities, is preserved. As a result, memory space is decreased, matching rules are simplified and computation cost is reduced. In addition, a scheme controlling the distance of neighbors for disparity smoothness is inserted to obtain a wide-area consistency of disparities, like a result of coarse-to-fine matchers. Because of this scheme, the proposed algorithm can produce a stable disparity map with a small fixed-size window. Finally, an alterative version of the proposed algorithm without using probability vector is also presented for simpler set-ups.

• Journal of Drive and Control
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• v.13 no.2
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• pp.34-41
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• 2016

Unlike the commonly used On/Off solenoid, constant attraction force which is independent of plunger displacement is a considerably important characteristic to proportional solenoid of the EPPR Valve. Attraction force uniformity is mainly affected by the internal shape design parameters. Due to a number of shape design parameters, the optimal parameter values are very complex and time consuming to find by trial and error method. Much research has been conducted or are still in progress to find the optimal parameter values by applying various optimization techniques like Genetic Algorithm, Evolution Strategy, Simulated Annealing, or the Taguchi method. In this paper, the design parameters which have primary effects on the attraction force uniformity and the average attraction force are decided by main effects analysis of Design of Experiments. Optimal parameter values are derived using finite-element analysis and a neural network model.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.278-286
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• 2020

The prisoner's dilemma game which is a representative example of game theory is being studied with interest by many economists, social scientists, and computer scientists. In recent years, many researches on computational approaches that apply evolutionary computation techniques such as genetic algorithms and particle swarm optimization have been actively conducted to analyze prisoner dilemma games. In this study, we intend to evolve a strategy for a iterated prisoner dilemma game participating two or more players using three different binary particle swarm optimization techniques. As a result of experimenting by applying three kinds of binary particle swarm optimization to the iterated prisoner's dilemma game, it was confirmed that mutual cooperation can be established even among selfish participants to maximize their own gains. However, it was also confirmed that the more participants, the more difficult to establish a mutual cooperation relationship.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.2
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• pp.143-149
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• 2022

The diffusion of OTT service has brought the fundamental changes in the value chain of the existing media industry. OTT service based on the public Internet has increased the number of subscribers by using dominant marketing capability, making the pay TV platform player's ability to connecting users powerless. This study examined the changes in the media market and pay TV industry in the USA due to the diffusion of OTT service and analyzed the changing strategies of media firms. The number subscribers of the expensive pay TV service in the USA has diminished, experiencing cord cutting and cord shaving due the diffusion of OTT. OTT players are changing the media market, showing the dramatic excellence in making original contents and distributing the newly released movies. Examination of the recent merger and acquisition cases of media firms tells that the investment in making original contents has increased in order to have the competitiveness in OTT business. The future media industry will be rapidly reshaped mainly based OTT service and strategic judgement is important to maintain the competitiveness of all media firms in the existing value chain of media industry.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1041-1046
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• 2022

Nucleoside deoxyribosyltransferase (NDT) is an enzyme that replaces the purine or pyrimidine base of 2'-deoxyribonucleoside. This enzyme is generally used in the nucleotide salvage pathway in vivo and synthesizes many nucleoside analogs in vitro for various biotechnological purposes. Since NDT is known to exhibit relatively low reactivity toward nucleoside analogs such as 2'-fluoro-2'-deoxynucleoside, it is necessary to develop an enhanced NDT mutant enzyme suitable for nucleoside analogs. In this study, molecular evolution strategy via error-prone PCR was performed with ndt gene derived from Lactobacillus leichmannii as a template to obtain an engineered NDT with higher substrate specificity to 2FDU (2'-fluoro-2'-deoxyuridine). A mutant library of 214 ndt genes with different sequences was obtained and performed for the conversion of 2FDU to 2FDA (2'-fluoro-2'-deoxyadenosine). The E. coli containing a mutant NDT, named NDT^L59Q, showed 1.7-fold (at 40℃) and 4.4-fold (at 50℃) higher 2FDU-to-2FDA conversions compared to the NDT^WT, respectively. Subsequently, both NDT^WT and NDT^L59Q enzymes were over-expressed and purified using a His-tag system in E. coli. Characterization and enzyme kinetics revealed that the NDT^L59Q mutant enzyme containing a single point mutation of leucine to glutamine at the 59^th position exhibited superior thermal stability with enhanced substrate specificity to 2FDU.

• Journal of Sensor Science and Technology
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• v.30 no.6
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• pp.369-375
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• 2021

In this study, heterogeneous ZnO/CNTF composites were developed to improve the NO₂-sensing response, facilitated by the self-heating property. Highly conductive and mechanically stable CNTFs were prepared by a wet-spinning process assisted by the liquid crystal (LC) behavior of CNTs. Metal-organic frameworks (MOFs) of ZIF-8 were precipitated on the surface of the CNTF (ZIF-8/CNTF) via one-pot synthesis in solution. The subsequent calcination process resulted in the formation of the ZnO/CNTF composites. The calcination temperatures were controlled at 400, 500, and 600 ℃ in an N₂ atmosphere to confirm the evolution of the microstructures and NO₂-sensing properties. Gas sensor characterization was performed at 100 ℃ by applying a DC voltage to induce Joule heating through the CNTF. The results revealed that the ZnO/CNTF composite after calcination at 500 ℃ (ZnO/CNTF-500) exhibited an improved response (R_air/R_gas = 1.086) toward 20 ppm NO₂ as compared to the pristine CNTF (R_air/R_gas = 1.063). Selective NO₂-sensing properties were demonstrated with negligible responses toward interfering gas species such as H₂S, NH₃, CO, and toluene. Our approach for the synthesis of MOF-driven ZnO/CNTF composites can provide a new strategy for the fabrication of wearable gas sensors integrated with textile materials.

• Smart Structures and Systems
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• v.31 no.4
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• pp.421-436
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• 2023

This paper presents a vibration displacement measurement and damage identification method for a space truss structure from its vibration videos. Features from Accelerated Segment Test (FAST) algorithm is combined with adaptive threshold strategy to detect the feature points of high quality within the Region of Interest (ROI), around each node of the truss structure. Then these points are tracked by Kanade-Lucas-Tomasi (KLT) algorithm along the video frame sequences to obtain the vibration displacement time histories. For some cases with the image plane not parallel to the truss structural plane, the scale factors cannot be applied directly. Therefore, these videos are processed with homography transformation. After scale factor adaptation, tracking results are expressed in physical units and compared with ground truth data. The main operational frequencies and the corresponding mode shapes are identified by using Subspace Stochastic Identification (SSI) from the obtained vibration displacement responses and compared with ground truth data. Structural damages are quantified by elemental stiffness reductions. A Bayesian inference-based objective function is constructed based on natural frequencies to identify the damage by model updating. The Success-History based Adaptive Differential Evolution with Linear Population Size Reduction (L-SHADE) is applied to minimise the objective function by tuning the damage parameter of each element. The locations and severities of damage in each case are then identified. The accuracy and effectiveness are verified by comparison of the identified results with the ground truth data.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.26 no.5
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• pp.249-265
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• 2023

Purpose: Infant regurgitation is associated with other functional gastrointestinal disorders and signs and symptoms that have a major impact on the quality of life of infants and their families. This study evaluated the safety, tolerance, and real-world effectiveness of an anti-regurgitation formula containing locust bean gum (LBG), prebiotics, and postbiotics to alleviate digestive symptoms beyond regurgitation. Methods: This 3-month study involved infants with regurgitation requiring the prescription of an anti-regurgitation formula according to usual clinical practice. Outcomes included evaluation of the evolution of stool consistency and frequency; occurrence of colic, constipation, and diarrhea; and assessment of regurgitation severity. Infant crying, parental assessment of infant well-being, and parental satisfaction with the stool consistency were also evaluated. Results: In total, 190 infants (average age: 1.9±1.1 months) were included. After three months, stool frequency and consistency remained within the normal physiological range, with 82.7% of infants passing one or two stools per day and 90.4% passing loose or formed stools. There was no significant increase in the number of infants with diarrhea, whereas a decrease was observed in the number of infants with constipation after 1 month (p=0.001) and with colic after both 1 and 3 months (p<0.001). Regurgitation severity and crying decreased and parental satisfaction with stool consistency, formula acceptability, infant well-being, and sleep quality increased. Monitoring of adverse events did not reveal any safety concerns. Conclusion: Formulas containing LBG, prebiotics, and postbiotics were well tolerated and provided an effective strategy for managing infant regurgitation and gastrointestinal discomfort.