• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.41 no.5
• /
• pp.35-44
• /
• 2004

With increase in digitalmedia data, various video indexing and video sequence matching algorithms have been proposed to efficiently manage and utilize digital media. In this paper, we propose a robust video indexing algorithm to detect scene changes for video sequences with abrupt luminance variations and an efficient video sequence matching algorithm for video sequence query. To improve the accuracy and to reduce the computational complexity for video indexing with abrupt luminance variations, the proposed algorithm utilizes edge features as well as color features, which yields a remarkably better performance than conventional algorithms. In the proposed algorithm first we extract the candidate shot boundaries using color histograms and then determine using edge matching and luminance compensation if they are shot boundaries or luminance changes. If the scene contains trivial brighness variations, the edge matching and luminance compensation are performed only for shot boundaries. In experimental results, the proposed method gives remarkably a high performance and efficiency than the conventional methods with the similar computational complexity.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.12A
• /
• pp.1833-1843
• /
• 1999

in this paper, we analyze the effects of PN sequence phase on the multiple access interference (MAI) of multi-media multi-rate DS/CDMA system with variable spreading gain (VGS) scheme, and furthermore derive the bit error rate (BER) equation for MAI users with different powers and spreading gains. In the sequel, we verify the influences of deterministic sequences on the bit error rate performance. As the results of the bit error rate of a desired user against interfering users with different spreading gains and different transmit powers, it is shown that the domain factor to determine the MAI component could be different according to the data transmission rate of a desired user. We also show that any kind of PN sequence phase does not yield considerable advantage, unless $E_b/N_o$ is considerably greater than 10dB, since below that value AWGN dominates. However, when the higher $E_b/N_o$, the performance of both MSQCC/CO and CO/MSQCC criterion give the better results.

• The KIPS Transactions:PartD
• /
• v.18D no.2
• /
• pp.81-88
• /
• 2011

Sequential pattern mining that determines frequent patterns appearing in a given set of sequences is an important data mining problem with broad applications. For example, sequential pattern mining can find the web access patterns, customer's purchase patterns and DNA sequences related with specific disease. In this paper, we develop the sequential pattern mining algorithms using MapReduce framework. Our algorithms distribute input data to several machines and find frequent sequential patterns in parallel. With synthetic data sets, we did a comprehensive performance study with varying various parameters. Our experimental results show that linear speed up can be achieved through our algorithms with increasing the number of used machines.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.1 s.343
• /
• pp.121-126
• /
• 2006

This paper report on the design and implementation of a 9.6kbps DSSS CDMA modem for a medium speed wireless link. The proposed modem provides a general purpose I/O interface with a microprocessor. The I/O interface consists of 8-bit data bus, chip enable, read/write, and interrupt pins. In transmit block, the 8-bit data delivered from the I/O interface buffer is converted to 9.6kbps serial data, which are spreaded into 76.8kcps with 8-bit PN code generated inside the modem by direct sequence method. An 8-bit training sequence is preceded in the data frame for data synchronization in receiver. In receiver block the PN code is synchronized from the received data spreaded to 76.8kcps and find the data timing from the 8-bit training sequence. We have used the Early-and-Late integration method. The modem has been implemented and verified using a Xilix FPGA board and has been fabricated as an ASIC CHIP through Hynir $0.25{\mu}m$ CMOS. The multiple accessing method is DSSS CDMA.

• The Journal of the Acoustical Society of Korea
• /
• v.22 no.1
• /
• pp.42-47
• /
• 2003

This paper proposes the method to generate new test data using the sample shift of the start frame for SPRT(sequential probability ratio test) in speaker verification. The SPRT method is a effective algorithm that can reduce the test computational complexity. However, in making the decision procedure, SPRT can be executed on the assumption that the input samples are usually to be i.i.d. (Independent and Identically Distributed) samples from a probability density function (pdf), also it's not suitable method to apply for the short utterance. The proposed method can achieve SPRT regardless of the utterance length of the test data because it is method to generate the new test data through the sample shift of start frame. Also, the correlation property of data to be considered in the SPRT method can be effectively removed by employing the principal component analysis. Experimental results show that the proposed method increased the computational complexity of data for sample shift a little, but it has a good performance result more than a conventional method above the average 0.7% in EER (equal error rate).

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.10b
• /
• pp.61-63
• /
• 2004

DTD에 의해서 문서의 형식이 정의된 valid XML을 XML 데이터베이스 시스템을 사용하여 관리하는 경우 XML의 변경은 그 변경 결과가 DTD에 대한 유효성(validity)을 만족시킬 때에만 수행되어야 한다. 이것은 다수의 사용자에 의해서 데이터가 공유되는 데이터베이스 시스템의 데이터 무결성과 관련되는 문제이기 때문에 XML 문서 변경에 대한 DTD 유효성은 XML 데이터베이스 시스템에서 중요한 속성이라고 할 수 있다. 변경 연산의 결과에 대한 XML의 유효성을 보장하기 위해서 변경의 유효성을 검증하는 방법을 사용할 수 있다 XML에서의 엘리먼트들은 순서 관계를 가질 수 있으며 DTD는 이러한 엘리먼트 순서 관계들을 정의하고 있기 때문에 이러한 유효성 검증 기법은 변경되는 데이터 아이템 외에도 주변의 데이터 아이템-엘리먼트-들에 대한 순서 정보를 필요로 한다. 그리고 데이터베이스와 같은 다중 사용자 환경에서 유효성 검증 기법이 정확하게 수행되기 위해서는 유효성 검증이 필요한 정보들이 다른 트랜잭션에 더해 변경되지 않도록 하는 병행수행 제어 기법을 필요로 한다 이렇게 유효성 검증 기법과 병행수행 제어 기법이 관련을 가지고 있음에도 불구하고 기존의 유효성 검증 기법은 오직 검증의 효율성에만 초점을 맞추고 있다. 본 연구는 유효성 검증의 검증 범위를 최소화 시켜 pan-out 값이 큰 XML 문서에 대해서도 유효성 검증이 효율적으로 수행될 수 있고, 또한 유효성 검증을 위해 락킹되는 데이터 아이템의 수란 최소화 할 수 있는 시퀀스 그룹 검증 기법을 제안한다. 또한 이 검증 기법의 정확을 보장하면서도 높은 트랜잭션 병행수행 성능을 보장한 수 있는 경계 락킹 기법을 제안한다. 제안된 유효성 검증 기법과 경계 락킹 기법은 유효성 검증의 정확성을 일해 병행수행 성능이 저하될 수바에 없는 기존의 기법들의 문제점들을 해결하여 XML 데이터 베이스 시스템이 안정적인 성능을 제공할 수 있다는 것을 실험을 통해 확인할 수 있었다.

• Journal of KIISE:Databases
• /
• v.34 no.1
• /
• pp.84-97
• /
• 2007

Selectivity estimation techniques in query optimization have been used in commercial databases and histograms are popularly used for the selectivity estimation. Recently, the techniques for spatio-temporal databases have been restricted to existing temporal and spatial databases. In addition, the selectivity estimation techniques focused on time-series data such as moving objects. It is also impossible to estimate selectivity for range queries with a time interval. Therefore, we construct two histograms, CMH (current multidimensional histogram) and PMH (past multidimensional histogram), to estimate the selectivity of multidimensional sequence data in spatio-temporal databases and propose effective selectivity estimation methods using the histograms. Furthermore, we solve a problem about the range query using our proposed histograms. We evaluated the effectiveness of histograms for range queries with a time interval through various experimental results.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.42 no.4
• /
• pp.739-746
• /
• 2017

Orthogonal frequency division multiplexing(OFDM) systems have many advantages. However, OFDM systems are much affected by a nonlinear distortion because those systems have a high peak to average power ratio(PAPR) value. A selected mapping technology was suggested to reduce a PAPR value. The technology does not have data loss but receivers need side information to know modified phase sequence. Therefore, side information causes decreased a transmission efficiency. In this paper, we suggest a blind SLM receiver using a cross correlation technology. This receiver does not require side information. The proposed blind SLM receiver calculates sums of cross-correlation between transmitted pilot signals multiplied by each phase sequence and received pilot signals. So, this receiver detects side information which has a maximum sum cross-correlation value. We compared our proposed SLM receiver to a conventional blind SLM receiver through bit error rate(BER) and side information error rate(SIER) performances. Simulation results show that the proposed SLM receiver has improved BER and SIER performances than the conventional SLM receiver.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.49 no.7
• /
• pp.12-22
• /
• 2012

The main drawback of the multi-code spread spectrum communication system, which spreads data bits stream by the multiplexed orthogonal codes, is the need for the highly linear amplifier. Several constant amplitude precoding schemes have been proposed for the Walsh code or the extended $m$-sequence based multi-code spread spectrum systems. In the constant amplitude spread spectrum systems the accompany code is transmitted together with orthogonal codes to maintain the transmitter output in a constant level. In this paper we propose the use of the accompany in the receiver to improve the BER performance. The proposed receiver has the capability to correct the code detection error(up to one code error). We carried out simulations to verify the validity of the proposed algorithm. BER performance improvement was noticed compared with the conventional receiver.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2022.11a
• /
• pp.606-608
• /
• 2022

센서 데이터를 활용한 행동 감지 연구는 인간 행동 인식을 선행연구로 진행되었으며, 인식의 정확도를 높이기 위해 전처리, 보간, 증강 등을 통한 연구가 활발히 진행되고 있다. 이에 본 논문에서는 시계열 센서 데이터 증강을 통하여 반려동물의 행동 감지를 제안한다. ODROID 단일 보드 컴퓨터와 6축 센서(가속도, 자이로) 데이터를 탑재한 소형 디바이스를 사용하여 블루투스 통신을 통해 웹 서버 DB에 저장한다. 저장된 데이터는 이상치, 결측치 처리 후 정규화를 통해 시퀀스를 구성하는 전처리 과정을 거친다. 이후 GAN을 기반으로 한 시계열 데이터 증강을 진행한다. 이때, 데이터 증강은 입력된 텍스트에 따라 센서 데이터로 변환하여 데이터를 증강한다. 학습된 딥러닝 모델을 바탕으로 행동을 감지 후 평가 지표에 따라 모델 성능을 검증한다.