• 한국HCI학회논문지
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• 제1권1호
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• pp.21-28
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• 2006

상용화된 웨어러블 컴퓨팅용 문자입력장치 중 팔목에착용하는 키보드가 많은데 대부분 소형화를 위해 키 수를 줄이는 방식을 택하고 있다. 하지만 충분한 착용성 확보를 위해 키보드의 키 수를 대폭 줄일 경우 보통 문자당 키입력수(KSPC)가 증가하기 때문에 입력효율이 저하되고 학습을 위해 부가적인 노력이 요구되는 등 우수한 웨어러블 키보드를 개발하는데 있어 착용성과 사용성이 상충하는 문제상황에 직면하게 된다. 본 연구는 이런 문제를 해결하기 위해 키 간격을 줄여 극적으로 키보드를 소형화할 수 있는 방법을 탐색하였다. 일련의 실험을 통해 키 간격 7mm인 키보드의 경우 물리적 폼팩터차원에서 착용성과 사회적 수용성이 충분히 긍정적이고 문자입력속도가 3세션 평균 15.0WPM 정도의 가능성 있는 결과를 도출했다. 하지만 수동적인 촉각 피드백과 입력에 대한 충분한 시각적 피드백의 부재가 문자입력수행도를 저하시킨다는 실험참가자들의 지적에 따라 원키 키보드라는 개념을 제안하였다. 전통적인 키보드의 경우 하나의 키에 하나의 문자가 할당한다. 반면 원키 키보드의 경우는 $70mm{\times}35mm$ 사이즈의 단일 키 위에 10*5배열의 QWERTY 키보드 문자배열을 모두 표시하였다. 따라서 일반적인 키보드와는 달리 키 판에서 어떤 문자를 입력했는지 키 입력 순간 손가락의 위치를 센싱하여 해당 문자를 계산하도록 하였다. 원키 키보드에 대한 입력효율 평가를 통해 5세션 평균 18.9WPM의 입력속도와 6.7%에러율을 기록했으면 최고 24.5WPM을 기록했다. 실험결과를 통해 본 연구에서 제안한 원키 키보드는 웨어러블 컴퓨팅 환경에서 착용성, 사회적 수용성, 입력효율성, 학습용이성 등의 상충적 요소에 대한 적절한 절충점을 제시하는 가능성 있는 문자입력장치로 평가되었다.

• 전자공학회논문지CI
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• 제45권6호
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• pp.60-67
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• 2008

RFID 시스템은 현재 다양한 분야에서 사용되어 지고 있는 바코드 인식 시스템이나 자기 인식 장치들이 근본적으로 내재하고 있는 실용성 및 보안성 문제점들을 보완할 수 있는 대체 시스템으로 각광받고 있다. 특히 RFID 시스템은 교통카드, 출입구 보안 및 출결 카드 분야를 포함한 상거래와 직접적인 관련이 있는 물류관리, 재고관리, 항만관리, 동물관리 등 물류 및 유통 분야에서도 빠르게 응용 및 확산되어 사용되어 지고 있다. 본 논문에서는 유비쿼터스 컴퓨팅의 한 예로서 RFID시스템을 TCP/IP를 이용하여 네트워크화하여 구성한 안전하고 효율적인 원격 출입 제어 시스템을 제안한다. 먼저 원격 출입 제어에 적합한 인증 프로토콜을 제안하며, 제안한 인증 프로토클 기반의 원격 보안 출입 제어 시스템이 원활한 자동문 제어가 가능함을 임베디드 시스템과 TCP/IP 기반의 RFID 시스템으로 구성된 자동문 세트를 활용한 모의실험을 통해 실용성을 증명한다.

• 의학교육논단
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• 제18권2호
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• pp.90-98
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• 2016

Assessment tools for non-academic qualities such as ethics frequently employ hypothetical scenarios to lay out a contextual framework underlying the corresponding criteria of assessment. Due to the context-specific nature of the assessment criteria, details of the scenarios become very important in obtaining accurate results. This study aims to explore how medical school applicants differ in ethical decision making depending on the types of ethical dilemma scenarios, and how they correlate with academic achievements after admission. In 2014, all 82 applicants invited for an admission interview for a graduate-entry program were asked to complete a questionnaire comprised of 13 hypothetical scenarios. There were three domains (unethical business decisions, unethical academic decisions, and sexual quid pro quos) and participants were made to choose between the profitable-but-unethical choice or the unprofitable-but-ethical choice, using a four-point Likert-type scale. On average, tendencies toward unethical decisions were lowest for sexual favors ($1.34{\pm}0.46$), and highest for gaining academic advantages ($2.22{\pm}0.56$). Unethical decisions for academic advantages and sexual benefits showed significant correlation respectively with the female gender and those who graduated from overseas universities. In addition, the propensity for choosing unethical academic decisions was significantly correlated with high academic achievements in medical school (r=0.396). Not only does this study demonstrate that different levels of ethical decision making depend on the scenarios, but also those differences may be a determinant factor in subsequent academic performances in medical school. In conclusion, given the possible influence of the details of the hypothetical scenarios to the applicant's responses, careful consideration must be given during their development.

• Advances in aircraft and spacecraft science
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• 제6권3호
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• pp.239-256
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• 2019

This study develops a dual purpose: i) evaluating the effects of two different Mars atmosphere models (NASA Glenn and GRAM-2001) on aerodynamics of a capsule (Pathfinder) entering the Mars atmosphere, ii) verifying the feasibility of evaluating the ambient density and pressure by means of the methods by McLaughlin and Cassanto, respectively and therefore to re-build the values provided by the models. The method by McLaughlin relies on the evaluation of the capsule drag coefficient, the method by Cassanto relies on the measurement of pressure at a point on the capsule surface in aerodynamic shadow. The study has been carried out computationally by means of: i) a code integrating the equations of dynamics of the capsule for the computation of the entry trajectory, ii) a DSMC code for the solution of the flow field around the capsule in the altitude interval 50-100 km. The models show consistent differences at altitudes higher than about 40 km. It seems that the GRAM-2001 model is more reliable than the NASA Glenn model. In fact, the NASA Glenn model produces, at high altitude, temperatures that seem to be too low compared with those from the GRAM-2001 model and correspondingly very different aerodynamic conditions in terms of Mach, Reynolds and Knudsen numbers. This produces pretty different capsule drag coefficients by the two models as well as pressure on its surface, making not feasible neither the method by McLaughlin nor that by Cassanto, until a single, reliable model of the Mars atmosphere is not established. The present study verified that the implementation of the Cassanto method in Mars atmosphere should rely (such as it is currently) on pressure obtained experimentally in ground facilities.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.764-771
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• 2010

The stability analysis method of an unsaturated slope considering the suction stress was performed on the infinite sand slope. During drying and wetting processes, the Soil-Water Characteristics Curve (SWCC) of the sand with the relative density of 75% was measured using the automated SWCC apparatus. Also, the Suction Stress Characteristics Curve (SSCC) was estimated. Based on these results, the stability analysis of an unsaturated infinite slope was carried out considering the slope angle, the weathering zone and the relative change in friction angle as a soil depth. According to the result of slope stability analysis, the safety factors of slope were less than 1 when the slope angles were more than $50^{\circ}$. The safety factors of slope tend to increase with increasing the depth from the ground surface. Especially, the safety factors have a tendency to increase and decrease above near the ground water level due to the suction stress. The maximum safety factor of slope in this analysis was occurred at the Air Entry Value (AEV) of drying process. The influence range of suction stress above the ground water level can be found out and can be defined as the funicular zone which means the metric suction range from the air entry point to the point of residual volumetric water content.

• 한국운동역학회지
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• 제16권1호
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• pp.139-149
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• 2006

This study is to analyze the kinematic variables of inward $1{\frac{1}{2}}$ somersault in platform diver. For the manner, 3 people form the national diving team in the year 2000were chosen as the subjects and two S-VHS video cameras set in 60frames/sec were used for recording their motions. Coordinated raw positions data through digitizing are smoothing by butter-worth's low-pass filterin method at a cut off frequency 6.0Hz. and the direct linear transformation(DLT) method was employed to obtain 3-D position coordinates. The conclusions were as follows. However, horizontal distance which is the change of the COG, form the point of the jump to the point of Event 3 where the player is out of the board range completely, Subject B showed 105.1cm and 71.1cm of the vertical distance which are shorter horizontal distance and higher vertical distance, thus, took a great advantage of the position to prepare for the entry. Therefore, if a player takes higher position by speeding up the vertical velocity at the moment of the jumping off the board, and stays in the air longer, the player can have more time to show his skill. Because of the use of the characteristics of the inward somersault, keeping the safe distance form the board is important but in order to higher the completeness, it is ideal to keep the horizontal distance little over 100cm. Also, the angles of shoulder and elbow from Event 1 to 4, depending on swing of the arms, motions in the air, getting ready for the entry, showed some difference individual by individual, according to the velocity of the thigh and shank showed much difference while getting ready and take-off, and it's because of the individual's different bending and straightening for horizontal and vertical distance.

• 디지털산업정보학회논문지
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• 제11권2호
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• pp.73-90
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• 2015

When we apply file commands on files in a directory, the directory as well as the file suffer changes in timestamps of MFT entry. Based on understanding of these changes, this work provides a digital forensic analysis on the timestamp changes of the directory influenced by execution of file commands. NTFS utilizes B-tree indexing structure for managing efficient storage of a huge number of files and fast lookups, which changes an index tree of the directory index when files are operated by commands. From a digital forensic point of view, we try to understand behaviors of the B-tree indexes and are looking for traces of files to collect information. But it is not easy to analyze the directory index entry when the file commands are executed. And researches on a digital forensic about NTFS directory and B-tree indexing are comparatively rare. Focusing on the fact, we present, in this paper, directory timestamp changes after executing file commands including a creation, a copy, a deletion etc are analyzed and a method for finding forensic evidences of a deletion of directory containing files. With some cases, i.e. examples of file copy and file deletion command, analyses on the problem of timestamp changes of the directory are given and the problem of finding evidences of a deletion of directory containging files are shown.

• 한국IT서비스학회지
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• 제10권4호
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• pp.243-258
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• 2011

With increasing interest in ubiquitous computing technology, an infrastructure for the short-distance wireless communication has been extended socially, bringing spotlight to the security system using the image or location. In case of existing security system, there have been issues such as the occurrences of blind spots, difficulty in recognizing multiple objects and storing of the unspecified objects. In order to solve this issue, zone-based location-estimation search system for the image have been suggested as an alternative based on the real-time location determination technology combined with image. This paper intends to suggest the search service for the image zone-based location-estimation. For this, it proposed the location determination algorism using IEEE 802.15.4/ZigBee's RSSI and for real-time image service, the RTP/RTCP protocol was applied. In order to combine the location and image, at the event of the entry of the specified target, the record of the time for image and the time of occurrence of the event on a global time standard, it has devised a time stamp, applying XML based meta data formation method based on the media's feature data based in connection with the location based data for the events of the object. Using the proposed meta data, the service mode which can search for the image from the point in time when the entry of the specified target was proposed.

• 수산해양교육연구
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• 제27권1호
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• pp.262-272
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• 2015

The aim of this study is to analysis factors that determine the competitiveness of container ports using the KJ and AHP methods. For this, 54 detailed attributing factors were identified both by previous studies and port users. 24 attributing factors were identified by a group of port experts. also, These were grouped 18 detailed attributing factors into 6 attributing factors by a group of port experts using the KJ method. These were made into a model of hierarchical structure with 3 levels, taking 1 goal factor, 6 evaluation factors and 18 detailed evaluation factors. The collected date of questionnaires were analyzed by a group of port experts using the AHP method. The analysis result of the evaluation factors in container port shows that port cargo volume is the most important factor, followed by port location, port cost, port service, port facility and port management. The analysis results of detailed evaluation factors in container port shows that import and export cargo volume is the most important factor, followed by transshipment cargo volume, distance from main trunk, cargo handling cost, distance from the point of importing and exporting, speediness of cargo handling, stability of cargo handling, vessel/cargo cost in port entry and leaving, punctuality in port entry and leaving, number and length of berth, collateral service cost, terminal area, hinterland accessibility, ability of terminal operation company, front depth of berth, etc.

• Geomechanics and Engineering
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• 제20권5호
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• pp.411-420
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• 2020

Numbers fitting-curve equations have been proposed to predict soil-water retention curve (SWRC) whose parameters have no definitude physical meaning. And these methods with precondition of measuring SWRC data is time-consuming. A simplified directly method to estimate SWRC without parameters obtained by fitting-curve is proposed. Firstly, the total SWRC can be discretized into linear segments respectively. Every segment can be represented by linear formulation and every turning point can be determined by the pore-size distribution (PSD) of Mercury Intrusion Porosimetry (MIP) tests. The pore diameters governing the air-entry condition (AEC) and residual condition (RC) can be determined by the PSDs of MIP test. The PSD changes significantly during drying in SWR test, so the determination of AEC and RC should use the PSD under corresponding suction conditions. Every parameter in proposed equations can be determined directly by PSD without curve-fitting procedure and has definitude physical meaning. The proposed equations give a good estimation of both unimodal and bimodal SWRCs.