• Korean Journal of Applied Biomechanics
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• v.27 no.2
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• pp.133-140
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• 2017

Objective: The purpose of this study was to determine the relationship between center of pressure (CoP) and local stability of the lower joints, which was calculated based on approximate entropy (ApEn) during walking in elderly women. Method: Eighteen elderly women were recruited (age: $66.4{\pm}1.2yrs$; mass: $55.4{\pm}8.3kg$; height: $1.56{\pm}0.04m$) for this study. Before collecting data, reflective marker triads composed of 3 non-collinear spheres were attached to the lateral surface of the thigh and shank near the mid-segment to measure motion of the thigh and shank segments. To measure foot motion, reflective markers were placed on the shoe at the heel, head of the fifth metatarsal, and lateral malleolus, and were also placed on the right anterior-superior iliac spine, left anterior-superior iliac spine, and sacrum to observe pelvic motion. During treadmill walking, kinematic data were recorded using 6 infrared cameras (Oqus 300, Qualisys, Sweden) with a 100 Hz sampling frequency and kinetic data were collected from a treadmill (Instrumented Treadmill, Bertec, USA) for 20 strides. From kinematic data, 3D angles of the lower extremity's joint were calculated using Cardan technique and then ApEn were computed for their angles to evaluate local stability. Range of CoP was determined from the kinetic data. Pearson product-moment and Spearman rank correlation coefficient were applied to find relationship between CoP and ApEn. The level of significance was determined at p<.05. Results: There was a negative linear correlation between CoP and ApEn of hip joint adduction-abduction motion (p<.05), but ApEn of other joint motion did not affect the CoP. Conclusion: It was conjectured that ApEn, local stability index, for adduction/abduction of the hip joint during walking could be useful as a fall predictor.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.417-429
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• 2015

Evaluation of traffic data quality is a backbone of better traffic information and management systems because it directly affects the reliability of traffic information. This study developed an integrated index for evaluating the quality of archived intelligent transportation systems (ITS) data. Two novel indices including spatio-temporal consistency and severity of missing data were devised and integrated with existing indices such as availability and completeness. An evaluation framework was proposed based on the developed integrated index. Both analytical hierarchical analysis (AHP) technique and entropy method were adopted to derive mixed weighting values to be used for the integrated index. It is expected that the proposed methodology would be effectively used in enhancing the quality of traffic data as a part of traffic information system.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.2
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• pp.63-73
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• 2020

Purpose: To investigate breathing-related changes in the balance ability of healthy adults. Methods: The participants were 36 healthy adults in their 20s and 30s. All participants were trained in three breathing (neutral, thoracic, and abdominal) methods one week before measurements. We used AccuSway to measure each participant's balance ability, using each breathing technique, in two postures (bipedal and unipedal). Results: During the bipedal balance task, abdominal breathing produced significant increases in path length and sway velocity. Abdominal breathing resulted in significant changes in sample entropy at the anteroposterior location compared with neutral breathing (p<.05). In the normalized anteroposterior location, there were significant changes in backward movement during thoracic and abdominal breathing compared with those during neutral breathing (p<.05). During the unipedal balance task, path length and sway velocity increased significantly during voluntary breathing compared with those during neutral breathing (p<.05). There was a significant change in backward movement when abdominal breathing-compared with neutral breathing-was used in the normalized anteroposterior location (p<.05). In the normalized left-right location, there was a significant shift to the right during thoracic breathing compared with that during neutral breathing (p<.05). Conclusion: Compared with neutral breathing, altered voluntary breathing patterns affect balance in healthy adults. Our results indicated that that static balance was more affected by abdominal breathing than by neutral breathing. Future studies should examine variables such as the breathing volume, rhythm, and method.

• Korean Journal of Food Science and Technology
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• v.15 no.4
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• pp.315-320
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• 1983

The water vapor sorption isotherms for a great variety of agricultural products were determined by using the standard salt solution technique at the temperatures of $25^{\circ},\;35^{\circ}\;and\;45^{\circ}C$. The B.E.T. monomolecular layer moisture contents were evaluated from experimental data on the sorption isotherms, and an analysis was made of the thermodynamic functions for water vapor sorption behaviors with respect to the storage stability of dehydrated foods. It may be concluded that the variation of entropy with moisture content of some agricultural products and seaweeds investigated would be a guide for the elucidation of the storage stability of dehydrated foods.

• Journal of the Korea Society of Computer and Information
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• v.11 no.1 s.39
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• pp.139-145
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• 2006

Feature extraction technique in digital images has many applications such as robot vision, medical diagnostic system, and motion video transmission, etc. There are several methods for extracting features in digital images for example nonlinear gradient, nonlinear laplacian, and entropy convolutional filter. However, conventional convolutional filters are usually not efficient to extract features in an image because image feature formation in eyes is more sensitive to dark regions than to bright regions. A few nonlinear filters using difference between arithmetic mean and harmonic mean in a window for extracting sketch features are described in this paper They have some advantages, for example simple computation, dependence on local intensities and less sensitive to small intensity changes in very dark regions. Experimental results demonstrate more successful features extraction than other conventional filters over a wide variety of intensity variations.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.36-43
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• 2009

In this paper, we propose a Cooperative Routing using ARQ-based Transmission (CRARQ) in Mobile Ad-hoc Wireless Sensor Networks (MAWSN). The goals of the CRARQ are to improve both the efficiency of transmission and the reliability of transmission together. The main features and contributions of the proposed CRARQ for supporting these goals are as follows. First, CRARQ uses a reactive concept to construct a route from a source to a destination. Second, CRARQ chooses the most stable relay at each hop along the route by mobility-based strategy. Third, cooperative transmission using the ARQ technique which can improve reliability is used at each hop to send data packets from source to destination. Finally, we present a theoretical analysis model for the proposed CRARQ. The performance evaluation of our protocol is implemented via simulation using Optimized Network Engineering Tool (OPNET) and analysis. The results of both simulation and analysis show that CRARQ achieves the improved packet delivery ratio (PDR) and outage probability.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.677-690
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• 1995

In this paper, we propose the high efficiency data compression capable of error control using block-sorting, move to front(MTF) and arithmetic code with variable length in to fixed out. First, the substring with is parsed into length N is shifted one by one symbol. The cyclic shifted rows are sorted in lexicographical order. Second, the MTF technique is applied to get the reference of locality in the sorted substring. Then the preprocessed sequence is coded using VF(variable to fixed) arithmetic code which can be limited the error propagation in one codeword. The key point is how to split the fixed length codeword in proportion to symbol probabilities in VF arithmetic code. We develop the new VF arithmetic coding that split completely the codeword set for arbitrary source alphabet. In addition to, an extended representation for symbol probability is designed by using recursive Gray conversion. The performance of proposed method is compared with other well-known source coding methods with respect to entropy, compression ratio and coding times.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.4
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• pp.421-430
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• 2010

Image segmentation technique is becoming increasingly important in the field of remote sensing image analysis in areas such as object oriented image classification to extract object regions of interest within images. This paper presents a new method for image segmentation in High Resolution Remote Sensing Image based on Improved Seeded Region Growing (ISRG) and Region merging. Firstly, multi-spectral edge detection was done using an entropy operator in pan-sharpened QuickBird imagery. Then, the initial seeds were automatically selected from the obtained multi-spectral edge map. After automatic selection of significant seeds, an initial segmentation was achieved by applying ISRG to consider spectral and edge information. Finally the region merging process, integrating region texture and spectral information, was carried out to get the final segmentation result. The accuracy assesment was done using the unsupervised objective evaluation method for evaluating the effectiveness of the proposed method. Experimental results demonstrated that the proposed method has good potential for application in the segmentation of high resolution satellite images.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.179-186
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• 2018

The number of devices connect to the internet is rapidly increasing with the advent of the IoT(Internet of Things). The IoT has improved the convenience of life. However, it makes security issues such as privacy violations. Therefore cybersecurity is the most important issue to be discussed nowadays. Especially, various protocols are used for same purpose due to rapidly increase of IoT market. To deal with this security threat noble vulnerability analysis is needed. In this paper, we contribute to the IoT security by proposing a new randomness-based test case evaluation methodology using variance and entropy. The test case evaluation method proposed in this paper can evaluate the test cases at a high speed regardless of the test set size, unlike the traditional technique.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.643-643
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• 2015

최근 북한의 수자원에 대한 관심과 연구가 활발히 이루어지고 있다. 또한, 수자원 취약성과 지속가능한 개발과 관련된 지수에 대한 연구도 꾸준히 이루어지고 있으며, 이 지수를 이용하여 현재 또는 미래의 수자원 취약성을 판단하고 대비하고 있다. 본 연구는 기상청, 통계청, 환경부에서 제공하는 자료 중에서 북한의 지역별 자료의 확보 가능한 자료를 대상으로 기후변화에 대한 기후노출, 민감도, 적응능력을 나타내는 지표들을 선정하여 남한과 북한의 26개 광역자치단체에 대하여 수자원 취약성 순위를 도출하였다. 기후변화를 고려한 지표들은 각각 홍수피해와 물부족을 반영하는 지표인 일최대강수량, 일강수량이 80mm 이상인 날의 수, 연최대 연속강우일수, 3일주기 최대 강수량, 6-9월 강수량, 12-2월 증발산량, 3-5월 증발산량, 12-2월 강수량, 3-5월 강수량, 연속적인 무강우일 수의 최대값, 총인구, 인구밀도를 선택하였으며, 변수들의 가중치 결정은 객관적 가중치 산정 방법인 Shannon의 entropy 기법과 주관적 가중치인 환경부(2012)에서 전문가를 대상으로 유도한 가중치를 적용하여 치수와 이수분야에 대한 취약성을 각각 평가하였다. 수자원 취약성의 정량적 평가를 위하여 TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) 기법을 적용하여 남 북한 지역별 수자원 취약성을 지수화하고 취약성 순위를 도출하였다. 산정된 수자원 취약성 지수가 낮을수록 취약함의 정도가 심각한 것으로 정의할 수 있으며, 연구결과 남 북한을 통틀어서 서울이 가장 취약한 지역으로 나타났으며, 치수 분야에서는 북한의 양강도가 취약성이 낮은 것으로 나타났고, 이수분야에서는 북한의 양강도와 남한의 제주도가 취약성이 낮은 것으로 나타났다. 따라서 본 연구는 남 북한의 지역별 취약성 순위를 통해 우리나라와 북한 수자원의 현황을 제시하며, 미래의 국가 수자원 계획 수립 및 대책을 제시할 수 있는 자료로 활용할 수 있을 것이다.