• 방송공학회논문지
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• 제21권3호
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• pp.436-449
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• 2016

본 논문에서는 MMT(MPEG Media Transport)와 MPEG-2 TS(Transport Stream)의 전달 오버헤드(overhead)를 비교한다. MPEG-2 TS는 DTV(Digital Television), IPTV(Internet Protocol Television), DMB(Digital Multimedia Broadcasting) 등 디지털 방송 분야에서 압축된 오디오 및 비디오 데이터를 다중화하여 전송하기 위한 프로토콜로서 전 세계적으로 널리 사용되고 있다. MPEG-2 TS 표준은 1990년대 초에 제정되었으며, 그 후 20여 년이 지나면서 MPEG-2 TS의 많은 부분들이 오늘날의 방송과 통신 환경에 적합하지 않게 되었다. 이러한 상황에서, 2014년 MPEG(ISO/IEC JTC 1 SC 29/WG 11)에서는 MPEG-2 TS를 대체할 수 있는 차세대 멀티미디어 전달 표준으로서 MMT를 표준화하였다. 본 논문에서는 방송 서비스 시나리오를 가정하고, MMT와 MPEG-2 TS를 적용하여 그에 따른 전달 오버헤드를 계산하였다. 본 논문을 위해 연구실에서 제작한 전달 오버헤드 계산 소프트웨어를 사용하였으며, 계산 결과를 바탕으로 이 두 방식의 전달 오버헤드를 비교, 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권7호
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• pp.2599-2613
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• 2015

Multi-index hashing (MIH) is the state-of-the-art method for indexing binary codes, as it di-vides long codes into substrings and builds multiple hash tables. However, MIH is based on the dataset codes uniform distribution assumption, and will lose efficiency in dealing with non-uniformly distributed codes. Besides, there are lots of results sharing the same Hamming distance to a query, which makes the distance measure ambiguous. In this paper, we propose a data-oriented multi-index hashing method (DOMIH). We first compute the covariance ma-trix of bits and learn adaptive projection vector for each binary substring. Instead of using substrings as direct indices into hash tables, we project them with corresponding projection vectors to generate new indices. With adaptive projection, the indices in each hash table are near uniformly distributed. Then with covariance matrix, we propose a ranking method for the binary codes. By assigning different bit-level weights to different bits, the returned bina-ry codes are ranked at a finer-grained binary code level. Experiments conducted on reference large scale datasets show that compared to MIH the time performance of DOMIH can be improved by 36.9%-87.4%, and the search accuracy can be improved by 22.2%. To pinpoint the potential of DOMIH, we further use near-duplicate image retrieval as examples to show the applications and the good performance of our method.

• 한국산학기술학회논문지
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• 제21권5호
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• pp.664-671
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• 2020

스마트 빌딩 (Smart Building)은 사물 인터넷 (IoT; Internet of Things) 장치와 클라우드 서비스에서 모두 사용될 수 있는 응응 프로그램을 의미한다. 최근 Amazon, Google 및 Microsoft와 같은 클라우드 서비스 제공 업체는 IoT 장치에서 클라우드 애플리케이션 서비스를 제공할 수 있는 IoT 클라우드 플랫폼을 제공하고 있다. Postscapes에 따르면 최근에 152 개의 IoT 클라우드 플랫폼이 존재하고 있으며 스마트 빌딩 구현을 위해 하나를 선택하는 것은 어려운 문제이다. 본 논문에서는 실험을 위해서 마이크로소프트 Azure IoT 허브와 아마존의 AWS(Amazon Web Services) IoT를 선택하였다. 두 개의 IoT 클라우드 플랫폼을 선택하고 스마트 빌딩 관점에서 평가하였다. IoT 클라우드 플랫폼을 평가하기 위해 두 가지 다른 IoT 클라우드 플랫폼을 활용하였고, 일반적인 스마트 빌딩 시나리오를 가정하여 프로토타입을 구현하였다. 실험은 IoT 클라우드 플랫폼을 사용하여 시스템을 개발하는 과정에서 얻은 정보와 경험을 기반으로 수행하였다. 이 평가 결과는 스마트 빌딩을 위해 IoT 클라우드 플랫폼을 선택할 때 활용될 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.1204-1227
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• 2020

The tradeoff between energy conservation and traffic balancing is a dilemma problem in Wireless Sensor Networks (WSNs). By analyzing the intrinsic relationship between cluster properties and long distance transmission energy consumption, we characterize three node sets of the cluster as a theoretical foundation to enhance high performance of WSNs, and propose optimal solutions by introducing rendezvous and Mobile Elements (MEs) to optimize energy consumption for prolonging the lifetime of WSNs. First, we exploit an approximate method based on the transmission distance from the different node to an ME to select suboptimal Rendezvous Point (RP) on the trajectory for ME to collect data. Then, we define data transmission routing sequence and model rendezvous planning for the cluster. In order to achieve optimization of energy consumption, we specifically apply the economic theory called Diminishing Marginal Utility Rule (DMUR) and create the utility function with regard to energy to develop an adaptive energy consumption optimization framework to achieve energy efficiency for data collection. At last, Rendezvous Transmission Algorithm (RTA) is proposed to better tradeoff between energy conservation and traffic balancing. Furthermore, via collaborations among multiple MEs, we design Two-Orbit Back-Propagation Algorithm (TOBPA) which concurrently handles load imbalance phenomenon to improve the efficiency of data collection. The simulation results show that our solutions can improve energy efficiency of the whole network and reduce the energy consumption of sensor nodes, which in turn prolong the lifetime of WSNs.

• 대한화학회지
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• 제46권5호
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• pp.450-468
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• 2002

컴퓨터의 보급이 늘어나면서 여러 분야에서 컴퓨터를 유용하게 사용하고 있다. 교육 분야 중 특히 과학을 학습하기 위한 자료로 멀티미디어를 사용하는 것들이 많다. 최근에는 학습자의 흥미와 관심을 이끌기 위해 자바나 플래시를 사용한 웹 기반 자료들이 증가하고 있다. 이렇게 컴퓨터 분양의 표현, 저장, 계산 및 통신 기술의 발달로 새로운 교육환경이 제공되고 있다. 특히 인터넷과 가상현실 기술은 교육환경에서 큰 변화를 가져올 것으로 판단되고 있다. 가상 현실 기법으로 가장 큰 특징은 실시간 상호작용이다. 최근의 연구에 의하면 학습자의 참여를 증가시키기 위해 화학 교육에서 가상현실 시뮬레이션을 사용하고 있으며 그 결과 화학의 기본 개념에 대한 이해가 진작되었고 실험실활동을 보강할 수 있다고 보고되었다. 이에 본 연구에서는 화학 교육에서 가상현실 기법의 활용 방안에 대해 고찰하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권10호
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• pp.3708-3728
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• 2021

Indian herbal plants are used in agriculture and in the food, cosmetics, and pharmaceutical industries. Laboratory-based tests are routinely used to identify and classify similar herb species by analyzing their internal cell structures. In this paper, we have applied computer vision techniques to do the same. The original leaf image was preprocessed using the Chan-Vese active contour segmentation algorithm to efface the background from the image by setting the contraction bias as (v) -1 and smoothing factor (µ) as 0.5, and bringing the initial contour close to the image boundary. Thereafter the segmented grayscale image was fed to a leaky capacitance fired neuron model (LCFN), which differentiates between similar herbs by combining different groups of pixels in the leaf image. The LFCN's decay constant (f), decay constant (g) and threshold (h) parameters were empirically assigned as 0.7, 0.6 and h=18 to generate the 1D feature vector. The LCFN time sequence identified the internal leaf structure at different iterations. Our proposed framework was tested against newly collected herbal species of natural images, geometrically variant images in terms of size, orientation and position. The 1D sequence and shape features of aloe, betel, Indian borage, bittergourd, grape, insulin herb, guava, mango, nilavembu, nithiyakalyani, sweet basil and pomegranate were fed into the 5-fold Bayesian regularization neural network (BRNN), K-nearest neighbors (KNN), support vector machine (SVM), and ensemble classifier to obtain the highest classification accuracy of 91.19%.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권11호
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• pp.2945-2965
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• 2023

The laser inertial measurement unit is a precision device widely used in rocket navigation system and other equipment, and its quality is directly related to navigation accuracy. In the quality evaluation of laser inertial measurement unit, there is inevitably uncertainty in the index input information. First, the input numerical information is in interval form. Second, the index input grade and the quality evaluation result grade are given according to different national standards. So, it is a key step to transform the interval information input by the index into the data form consistent with the evaluation result grade. In the case of uncertain input, this paper puts forward a method based on probability distribution to solve the problem of asymmetry between the reference grade given by the index and the evaluation result grade when evaluating the quality of laser inertial measurement unit. By mapping the numerical relationship between the designated reference level and the evaluation reference level of the index information under different distributions, the index evidence symmetrical with the evaluation reference level is given. After the uncertain input information is transformed into evidence of interval degree distribution by this method, the information fusion of interval degree distribution evidence is carried out by interval evidential reasoning algorithm, and the evaluation result is obtained by projection covariance matrix adaptive evolution strategy optimization. Taking a five-meter redundant laser inertial measurement unit as an example, the applicability and effectiveness of this method are verified.

• 기본간호학회지
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• 제11권1호
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• pp.6-12
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• 2004

Purpose: The purpose of this study was to evaluate self-study learning achievement in undergraduate nursing students who used a web-based wound care e-book. Method: The web-based wound care e-book was applied to 80 nursing students at Y university. The students studied the wound care e-book for four weeks and practiced wound dressing by themselves in open laboratory. Learning achievement was evaluated according to achievement of unit objectives and performance of an actual wound dressing. Result: 1. The total mean score for achievement of unit objectives was 3.06 (${\pm}0.41$) and the total mean score on the performance of the wound dressing was 89.40 (${\pm}5.47$). 2. There was no difference between the scores in the performance test (F=1.012, p=.366) for students who used self-study and those who were given a lecture. 3. A positive correlation was found between achievement of unit objectives and performance of the wound dressing (r=0.306, p<0.05). Conclusion: The web-based wound care e-book was effective in facilitating self-study for nursing students, and there is a need to continuously develop and up-date web-based nursing education e-books to facilitate self-study.

• Healthcare Informatics Research
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• 제24권4호
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• pp.283-291
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• 2018

Objectives: To identify the current status of smartphone usage and to describe the needs for smartphone-based cardiac telerehabilitation of cardiac patients. Methods: In 2016, a questionnaire survey was conducted in a supervised ambulatory cardiac rehabilitation (CR) program in a university affiliated hospital with the participation of heart failure or heart transplantation patients who were smartphone users. The questionnaire included questions regarding smartphone usage, demands for smartphone-based disease education, and home health monitoring systems. Results were described and analyzed according to principal diagnosis. Results: Ninety-six patients (66% male; mean age, $5{\pm}11$ years), including 56 heart failure and 40 heart transplantation patients, completed the survey (completion rate, 95%). The median daily smartphone usage time was 120 minutes (interquartile range, 60-300), and the most frequently used smartphone function was text messaging (61.5%). Of the patients, 26% stated that they searched for health-related information using their smartphones more than 1 time per week. The major source of health-related information was Internet browsing (50.0%), and the least sought source was the hospital's website (3.1%). Patients with heart failure expressed significantly higher needs for disease education on treatment plan, home health monitoring of blood pressure, and body weight (${\chi}^2=5.79$, 6.27, 4.50, p < 0.05). Heart transplantation patients expressed a significant need for home health monitoring of body temperature (${\chi}^2=5.25$, p < 0.05). Conclusions: Heart failure and heart transplantation patients show high usage of and interest in mobile health technology. A smartphone-based cardiac telerehabilitation program should be developed based on high demand areas and modified to suit to each principal diagnosis.

• 디자인학연구
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• 제17권3호
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• pp.147-156
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• 2004

지금까지, 웹사이트의 '사용성 테스트는(usability test)'는 피실험자에게 익숙하지 않아 자연스럽게 행동하기 힘든 '실험실 환경'에서 이뤄져왔다. 이 실험 방법은 또한 실험이 진행되는 동안 실험자가 실험자와 동일한 공간에 있어야하기 때문에 다수의 피실험자를 상대할 때 비효율적이다. 이는 실험실 기반의 사용성 테스트 법이 비용과 시간을 크게 줄일 수 있는 비동기(asynchronous)적 특성을 갖고 있지 않기 때문이다. 본 연구는 적은 수의 실험자가 다수의 피실험자를 대상으로 사용성 테스트 실험을 진행할 수 있는 비동기적 실험 방법을 제안하기 위해 문헌연구를 통해 기존의 사용성 테스트 방법과 원격 실험을 정리하였고, 이러한 연구를 바탕으로 웹사이트 원격 사용성 테스트 도구를 개발하였다. RIO라는 이름으로 개발된 도구는 웹사이트를 원격으로 사용성 평가하기 위한 태스크를 설계하는 '프로젝트 관리 모듈', 피실험자가 태스크를 수행하는 동안 인터랙션을 관찰/보고하는 '원격 인터랙션 관찰 브라우저 모듈', 수집된 인터랙션 데이터를 시각적으로 분석하는 '인터랙션 시각화/분석 모듈'로 구성되어 사용성 테스트 자료를 효율적으로 수집할 수 있는 소프트웨어 패키지의 구성과 수집 시나리오를 제안하였다.