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Han K.-S.,Sungkyul University
IEICE Transactions on Information and Systems | Year: 2017

This study proposes an effective pseudo relevance feedback method for information retrieval in the context of question answering. The method separates two retrieval models to improve the precision of initial search and the recall of feedback search. The topic-preserving query expansion links the two models to prevent the topic shift.

Shin K.C.,Sungkyul University
International Journal of Security and its Applications | Year: 2016

The design of the remote user authentication scheme for access to the service server is a very important issue in a multi-server environment. In particular, it is essential for mutual authentication and key agreement process between the user and the server. Proposed so far many schemes are focused to increase safety, reduce the communication time and calculation cost. On the other hand, there is a limit to overcome a variety of attacks. In recent years, Jain et al'.s proposed the authentication scheme, such as mutual authentication and session key establishment, smart card-based multi-server authentication scheme to withstand a variety of attacks. In this paper, I analyze that Jain et al'.s scheme is not secure against user impersonation attack, man-in-the-middle attack, DoS attack, reply attack etc. © 2016 SERSC.

Ethernet-Passive Optical Network (EPON) with the sleep mode has been considered for an attractive solution to achieve both cost-effective broadband access and energy reduction. To maximize both the QoS and the energy efficiency in the system, we propose a novel dynamic bandwidth allocation (DBA) which complements the existing fixed and limited service based bandwidth allocation schemes. The performance of the proposed scheme is evaluated in terms of the queuing delay, the jitter, and the energy efficiency according to various bandwidth allocation schemes and polling cycles. © 2016 American Scientific Publishers. All rights reserved.

Chin S.,Sungkyul University | Kim K.-Y.,Wayne State University
Computers in Industry | Year: 2010

To realize truly customer-oriented wearable products, individual users' unique characteristics and features should be properly captured and represented. This research focuses on an efficient methodology to generate low polygonal virtual human face models, which overcome the limitation of existing high polygonal models. To determine individuals' characteristics in the conceptual design stage of wearable products. A computerized and personalized 3D facemodel should be efficiently generated and be able to interact with wearable products. This research formulates a computerized 3D face via a 3D feature-based transformation. The developed algorithm is able to concisely and efficiently create a 3D face by using frontal and lateral pictures of users. The performance of this algorithmis well adapted both to typical PCs and to mobile devices. The generated virtual face models can serve as communication media in a multidevice based collaborative design environment. Through experiments, the validity of the proposed modeling method is considerably acceptable with respect to the quality of the similarity between 3D faces and individual pictures. Finally, this paper discusses how the developed personalized face modeling can be successfully utilized for customer-oriented wearable product design by showing compatible matching of a hairstyle product as a user study. © 2010 Elsevier B.V. All rights reserved.

Loh W.-K.,Sungkyul University | Moon Y.-S.,Kangwon National University | Srivastava J.,University of Minnesota
Information Sciences | Year: 2010

Efficient processing of streaming time-series generated by remote sensors and mobile devices has become an important research area. As in traditional time-series applications, similarity matching on streaming time-series is also an essential research issue. To obtain more accurate similarity search results in many time-series applications, preprocessing is performed on the time-series before they are compared. The preprocessing removes distortions such as offset translation, amplitude scaling, linear trends, and noise inherent in time-series. In this paper, we propose an algorithm for distortion-free predictive streaming time-series matching. Similarity matching on streaming time-series is saliently different from traditional time-series in that it is not feasible to directly apply the traditional algorithms for streaming time-series. Our algorithm is distortion-free in the sense that it performs preprocessing on streaming time-series to remove offset translation and amplitude scaling distortions at the same time. Our algorithm is also predictive, since it performs streaming time-series matching against the predicted most recent subsequences in the near future, and thus improves search performance. To the best of our knowledge, no streaming time-series matching algorithm currently performs preprocessing and predicts future search results simultaneously. © 2009 Elsevier Inc. All rights reserved.

Kim M.,Sungkyul University
Journal of Supercomputing | Year: 2016

With the development of web, the amount of information from science and technology is generated and managed in web environments. Then, many researchers are interested in the extracting and analyzing scientific issues from various science data. The proposed approach analyzed the issue keywords from metadata in research projects. Furthermore, we extracted the related science data, such as paper and patent, from science document database. The proposed approach performed social network analysis between typical science data. It generated the clusters which represent the scientific topics with time divisions. Moreover, we could deduce the relationship between science data and social data, such as newsletter and blog data. © 2016, Springer Science+Business Media New York.

Ko H.-K.,Sungkyul University
Lecture Notes in Electrical Engineering | Year: 2015

Secure dissemination of XML document is becoming a crucial requirement for many Web-based applications. By secure dissemination, we mean that the delivery of information to users must obey the access control policies. In this paper, we present an approach for the secure dissemination of web contents for users. Our approach uses a labeling scheme that protects the private information of web contents for users. Our experiment results show that the proposed approach is efficient protecting the private information. © Springer-Verlag Berlin Heidelberg 2015

Kim Y.S.,Sungkyul University
Expert Systems with Applications | Year: 2010

In this article, the performance of classification methods was empirically compared while varying the number of classes of dependent variables, the number of independent variables, the types of independent variables, the number of classes of the independent variables, and the sample size. Our study employed 324 simulated examples, with artificial neural networks and decision trees as the data mining techniques, and logistic regression as the statistical method. In the performance study, we use the misclassification errors as the metric and come up with some additional findings: (i) for continuous independent variables, a statistical technique (i.e., logistic regression) was superior to data mining techniques (i.e., artificial neural network and decision tree) when dependent variable has binary values, while the artificial neural network was best when the number of classes of dependent variable was three or more; (ii) for continuous and categorical independent variables, logistic regression performs better than artificial neural network and decision tree in the case of small number of independent variables and small sample size, while artificial neural network was best in other cases; and (iii) the artificial neural network performance improved faster than that of other methods as the number of independent variables and the number of classes of dependent variables increases. © 2009 Elsevier Ltd. All rights reserved.

Kim S.-G.,Yonsei University | Yun G.-H.,Sungkyul University | Yook J.-G.,Yonsei University
IEEE Transactions on Microwave Theory and Techniques | Year: 2012

In this paper, a compact vital signal sensing method using oscillation frequency deviation at 2.4-GHz industrial-scientific-medical band is proposed to detect vital signals, such as heartbeat and respiration signal. The oscillation circuit of the proposed vital sensor system has been realized by a planar resonator, which functions as a positive feedback element, as well as a near-field radiator to sense vital signals, simultaneously. The periodic movement of a body by respiration exercise causes the impedance variation of the radiator within the near-field range. The impedance variation results in a corresponding change in the oscillation frequency, and this variation has been utilized for sensing of the vital signals. In addition, a surface acoustic wave filter and power detector have been used to increase the sensitivity of the system and to transform the frequency variation to voltage waveform. The experimental results show that the proposed vital sensor placed 20 mm from the body can detect the heartbeat waveform very accurately. © 2006 IEEE.

Chung M.,Sungkyul University
Proceedings - 2016 IEEE 1st International Conference on Internet-of-Things Design and Implementation, IoTDI 2016 | Year: 2016

In this paper, we propose a new method for one-tomany data transmission in smart devices at close range. Existing methods require the use of an extra application service where the operating system differs between smart devices. In contrast, the proposed method makes use of the smart device's built-in speaker and microphone to confirm the transmission signal. Data is then transmitted via Wi-Fi or long term evolution. The proposed method therefore overcomes operating system issues with existing methods. Besides, BUMP technology works in a similar way to the method we propose, it only supports one-toone transmission. To evaluate the efficacy of the new method, we tested one-to-many data transmission in an experiment: the results showed a 96% success rate. As a result, we believe that the proposed method is an effective tool for one-to-many data transmission for smart devices at close range. © 2016 IEEE.

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