• KIPS Transactions on Computer and Communication Systems
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• v.7 no.6
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• pp.137-144
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• 2018

Vehicular Ad-hoc Networks (VANETS) have enabled to provide a variety of applications such as accident notification, content usage, etc. These applications have spatio-temporal data which have an interesting region and a lifetime according to their properties. However, geocasting protocols to deliver data to an interesting region can provide data to all vehicles in the region through a single transmission only at the current time, but cannot provide data to vehicles passing through the region during the lifetime of the data. Thus, we propose a spatio-temporal geocasting protocol called STGP using a regional caching scheme to send data to vehicles in an interesting region during a data lifetime in VANETs. For efficient and reliable regional caching, the proposed protocol uses the beacon-based data sharing, the extra caching elimination, and the distance-based caching exchange. Simulation results verify that the proposed protocol achieves more reliable and efficient data delivery compared with the existing protocol.

• Journal of Internet Computing and Services
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• v.16 no.3
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• pp.21-32
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• 2015

Since spatio-temporal local features for video representation have become an important issue of modeless bottom-up approaches in action recognition, various methods for feature extraction and description have been proposed in many papers. In particular, BoF(bag of features) has been promised coherent recognition results. The most important part for BoF is how to represent dynamic information of actions in videos. Most of existing BoF methods consider the video as a spatio-temporal volume and describe neighboring 3D interest points as complex volumetric patches. To simplify these complex 3D methods, this paper proposes a novel method that builds BoF representation as a way to learn 2D interest points directly from video data. The basic idea of proposed method is to gather feature points not only from 2D xy spatial planes of traditional frames, but from the 2D time axis called spatio-temporal frame as well. Such spatial-temporal features are able to capture dynamic information from the action videos and are well-suited to recognize human actions without need of 3D extensions for the feature descriptors. The spatio-temporal BoF approach using SIFT and SURF feature descriptors obtains good recognition rates on a well-known actions recognition dataset. Compared with more sophisticated scheme of 3D based HoG/HoF descriptors, proposed method is easier to compute and simpler to understand.

• Journal of KIISE:Information Networking
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• v.36 no.5
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• pp.425-436
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• 2009

In recent years, the user demands have increased for multimedia service of high quality over the broadband convergence network. These rising demands for high quality multimedia service led the popularization of various user terminals and large scale display equipments, which needs a variety type of QoS (Quality of Service). In order to support demands for QoS, numerous research projects are in progress both from the perspective of network as well as end system; For example, at the network perspective, QoS guaranteeing by improving of internet performance such as Active Queue Management, while at the end system perspective, SVC (Scalable Video Coding) encoding scheme to guarantee media quality. However, existing AQM algorithms have problems which do not guarantee QoS, because they did not consider the essential characteristics of video encoding schemes. In this paper, it is proposed to solve this problem by deploying the TS- AQM (Temporal Scalability Active Queue Management) which employs the differentiated packet dropping for dependency of the temporal level among the frames, based on SVC encoding characteristics by exploiting the TID (Temporal ID) field of the SVC NAL unit header. The proposed TS-AQM guarantees multimedia service quality through video decoding reliability for SVC streaming service, by differentiated packet dropping when congestion exists.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1205-1219
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• 2011

In this work, a stabilized characteristic finite volume method for the time-dependent Navier-Stokes equations is investigated based on the lowest equal-order finite element pair. The temporal differentiation and advection term are dealt with by characteristic scheme. Stability of the numerical solution is derived under some regularity assumptions. Optimal error estimates of the velocity and pressure are obtained by using the relationship between the finite volume and finite element methods.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.421-425
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• 2005

A distributed FBG temperature sensor system was constructed for the use in protection of electric power system. A F-P wavelength tunable filter is used converting temperature-induced wavelength variations to temporal peak locations. We used Gaussian line-fitted algorithm to alleviate the error caused by quantization and electrical noises. The experimental results showed much better accuracy than the raw peak-detection scheme.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.739-742
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• 1997

A remote drum grappling device coupled to the anti-swing crane has been developed by KAERI to cope with problems involved in manually treating low level waste drums. In order for this grappling device to be operated effectively, multi-sensors including CCD camera were employed. As an activity representation scheme of the device, Extended State Machine (ESM) was used to descibe its operation sequences. The performance testing of the device was conducted successfully, and consequently its application could be extendable to industrial operation environment.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.712-715
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• 1999

In this paper we propose high quality audio coding algorithm using psychoacoustic modelling and the adaptive wavelet Packet decomposition. The bit allocation scheme exploits the remnants of temporal correlations that exist in the wavelet packet coefficients by SPIHT. The proposed algorithm achieve almost transparent coding of monophonic compact disk(CD) quality signals at about 44 kbps.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.64-66
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• 2001

비디오 데이터는 미디어의 특성상 시간의 흐름에 따라 객체의 위치가 변하는 움직임 객체(Moving Object)를 가지며, 움직임 객체를 기반으로 비디오 데이트를 색인 및 검색하기 위해서는 적합한 시공간 표현 기법이 요구된다. 따라서 본 논문에서는 비디오 데이터가 지니는 움직임 객체의 움직임 경로(Trajectory)를 효율적으로 모델링하고 사용자에게 빠른 검색 결과를 제공할수 있는 근사 탐색(Approximation Search)이 가능한 새로운 시공간 표현 기법을 제안한다. 이는 사용자가 직접 스케치한 움직임 경로를 토대로 검색을 수행하는 내용 기반 검색과 움직임 객체의 일련의 움직임 경로들과 움직임 경로가 일어나는 위치 정보를 통해 얻어진 개념(의미)을 이용한 개념 기반 검색을 지원한다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.110-112
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• 2000

이미지와는 달리, 비디오 데이터는 객체에 대한 움직임 정보(motion trajectory)를 가지고 있으며, 이러한 움직임 정보는 비디오 데이터만이 가지는 매우 중요한 특징으로 비디오 데이터에 대한 색인과 내용 기반 검색을 수행하는 데 있어 중요한 역할을 한다. 따라서, 본 논문에서는 비디오 데이터베이스에서 효율적인 내용기반 검색을 위해 하나의 객체에 대한 움직임 정보를 나타내는 single motion trajectory와 두 객체에 대한 움직임 정보를 나타내는 multiple motion trajectory를 위한 새로운 시공간 표현 기법을 제안한다. 아울러, 움직임 정보에 대한 사용자 질의에 대해 유사성을 측정하여 순위부여와 Time Interval을 지원하는 새로운 유사성 측정 알고리즘인 SIST와 SIMT를 제안한다.

• Journal of the Optical Society of Korea
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• v.9 no.3
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• pp.95-98
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• 2005

We propose a two-dimensional temporal/wavelength optical code division multiple access (OCDMA) encoder/decoder, which has an array of superstructured fiber Bragg gratings (SSFBGs). SSFBGs in an encoder/decoder have different wavelengths from each other and can be coded with the same OCDMA code or not. Simulation was performed to analyze the feasibility of the scheme.