• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.484-490
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• 2016

Full-duplex communication can enhance wireless capacity by enabling simultaneous transmission and reception of the signals on the same frequency spectrum. Such a benefit, however, is only achieved when strong self-interference is well canceled below a sufficient level. To achieve this goal, there have been several approaches for cancellation, each of which is combined with digital-domain cancellation for a higher gain. In this paper, we implement two self-interference cancellation techniques and integrate them with a software defined radio-based wireless communication testbed. Two cancellation techniques (antenna cancellation and noise subtraction) are implemented and the cancellation gain is measured via real experiments. The results show that the gain of the antenna placement technique highly depends on the placement of a receiving antenna and the highest gain is achieved at the expected point, and we show that combining the noise subtraction circuit with the antenna placement further improves the cancellation gain.

• Journal of the Korean Society of Food Culture
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• v.25 no.3
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• pp.285-295
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• 2010

The purpose of this study was to compare the awareness of dietary patterns and health of full-time and employed housewives. The investigation gathered information on general characteristics, dietary lifestyle, nutritional status, and health by questionnaire as well as anthropometric measurements. The subjects included housewives living in Seoul and Gyeonggi Province (86 full-time and 127 working housewives) during November 2009 to January 2010. The average age, height, and weight of the housewives were $45.8{\pm}7.6\;yr$, $161.0{\pm}8.4\;cm$, and $55.7{\pm}6.3\;kg$, respectively. The average monthly income of the households was 3 million to 5 million won (31.4% full-time and 37.0% working housewives), and their average food expense was 200,000 to 500,000 won (46.5% full-time and 48.1% working housewives). More than 90% of the studied homes were nuclear families and the most common number of children was 2 to 3 (79.1% full-time and 76.4% working housewives). The ratio of employed housewives who ate regular meals was 35.4%, but that of the full-time housewives was 48.2% (p<0.05). Of the working housewives, 7.1% never ate breakfast and the primary reason for skipping breakfast was 'busy in the morning' (61.1%). The type of food that the housewives preferred when eating out was Korean food, both for the full-time and employed housewives (76.0%). All the housewives overate calories and the full-time housewives ate more protein, fat, vitamin A, vitamin B1, vitamin B6, niacin, vitamin C, vitamin E, folic acid, and cholesterol than the employed housewives (p<0.05). Both the full-time and employed housewives were more satisfied with supper than with other meals. About 30.6% of the full-time and 33.9% of the working housewives had no interest in health, but answered that regular exercise was very important for health (33.3% full-time and 39.7% working housewives). In conclusion, working housewives have poor dietary habits and nutrient intakes, thus substantial measures to improve these problems are urgently needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2363-2369
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• 2014

The DVR system supports multiple cameras and should be able to receive images at 30 frames per channel in real time. Thus, The system is using Full-HD-grade Multiplexer and Hardware compression codec. In this paper, Describing the design and implementation for the 4-channel Full-HD-grade PC-based DVR using FPGA and GPU inside CPU without Multiplexer and Hardware codec. The existing DVR system for Full-HD-grade has drawbacks to acquire images of about only 20 frames per channel in real time. The system to acquire images of multiple channel in real time was designed using FPGA. The software for the system was implemented using Intel Media SDK. At the result of performance evaluation, It was satisfied all for the required conditions. The practicality of the system was confirmed as implementation the system without using hardware compression.

• Journal of IKEEE
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• v.25 no.3
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• pp.517-527
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• 2021

This paper presents the phase-shift full-bridge DC-DC converter using the one-chip micom. The proposed converter primary is the full-bridge power topology that operates with the unipolar pulse-width modulation (PWM) by the phase-shift method, and the secondary is the full-bridge full-wave rectifier composed of four diodes. The control of proposed converter is performed by the one-chip micom and its MOSFET switches are driven by the bootstrap circuit. Thus the total system of proposed converter is simple. The proposed converter achieves high-efficiency using the resonant circuit and blocking capacitor. In this paper, first, the power-circuit operation of proposed converter is explained according to each operation mode. And the power-circuit design method of proposed converter is shown, and the software control algorithm on the micom and the feedback and switch drive circuits operating the proposed converter are described, briefly. Then, the operation characteristics of proposed converter are validated through the experimental results of a designed and implemented prototype converter by the shown design and implementation method in this paper. The highest efficiency in the results was about 92%.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.50.4-51
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• 2015

Current and planned deep multicolor wide-area cosmological surveys will map in detail the spatial distribution of galaxies and quasars over unprecedented volumes, and provide a number of objects with photometric redshifts more than an order of magnitude bigger than that of spectroscopic redshifts. Photometric information is statistically more significant for studying cosmological evolution, dark energy, and the expansion history of the universe at a fraction of the cost of a full spectroscopic survey, but intrinsically carries a bias due to noise in the distance estimates. We provide convolution- and deconvolution-based algorithms capable of removing this bias -- thus able to exploit the full cosmological information -- in order to reconstruct intrinsic distributions and correlations between distance-dependent quantities. We then show some direct applications of our techniques to the VIMOS Public Extragalactic Redshift Survey (VIPERS) and the Sloan Digital Sky Survey (SDSS) datasets. Our methods impact a broader range of studies, when at least one distance-dependent quantity is involved; hence, they will be useful for upcoming large-volume surveys, some of which will only have photometric information.

• Journal of Information Processing Systems
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• v.4 no.2
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• pp.67-76
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• 2008

This research proposes a new strategy where documents are encoded into string vectors and modified version of k means algorithm to be adaptable to string vectors for text clustering. Traditionally, when k means algorithm is used for pattern classification, raw data should be encoded into numerical vectors. This encoding may be difficult, depending on a given application area of pattern classification. For example, in text clustering, encoding full texts given as raw data into numerical vectors leads to two main problems: huge dimensionality and sparse distribution. In this research, we encode full texts into string vectors, and modify the k means algorithm adaptable to string vectors for text clustering.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.230-232
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• 2007

본 논문은 인간의 언어정보처리과정 중 초기 어휘획득(lexical acquisition) 과정을 한국어에 적용시켜 Full-List 모형과 Decomposition 모형의 하이브리드한 형태의 계산주의적 (computational) 어휘정보처리 모델을 구현하고 실험하였다. 실험결과 학습을 통한 언어적 입력의 인간의 어휘획득 과정을 모사(simulate) 할 수 있었고, 특정 문법범주 습득 순서에 대한 이론적 근간을 제시할 수 있었다. 또한 본 연구의 모델에서 자동으로 생성된 Full-List 사전과 Decomposition 사전을 통해 인간의 대뇌 심성표상(mental representation) 형태를 유추할 수 있는 증거를 보였다.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.127-130
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• 2007

The conventional feature recombination technique is very effective in the band-limited noise condition, but in broad-band noise condition, the conventional feature recombination technique does not produce notable performance improvement compared with the full-band system. To cope with this drawback, we introduce a new technique of sub-band likelihood computation in the feature recombination, and propose a new feature recombination method by using this sub-band likelihood computation. Furthermore, the reliable sub-band selection based on the signal-to-noise ratio is used to improve the performance of this proposed feature recombination. Experimental results shows that the average error reduction rate in various noise condition is more than 27% compared with the conventional full-band speaker identification system.

• Journal of information and communication convergence engineering
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• v.18 no.1
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• pp.33-38
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• 2020

Elasticsearch is an open source search and analytics engine that can search petabytes of data in near real time. It is designed as a distributed system horizontally scalable and highly available. It provides RESTful APIs, thereby making it programming-language agnostic. Full text search of multilingual text requires language-specific analyzers and field mappings appropriate for indexing and searching multilingual text. Additionally, a language detector can be used in conjunction with the analyzers to improve the multilingual text search. Elasticsearch provides more than 40 language analysis plugins that can process text and extract language-specific tokens and language detector plugins that can determine the language of the given text. This study investigates three different approaches to index and search Chinese, Japanese, and Korean (CJK) text (single analyzer, multi-fields, and language detector-based), and identifies the advantages of the language detector-based approach compared to the other two.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1145-1151
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• 2010

Hochwald et al. introduced unitary space-time codes for quasi-static Rayleigh fading channels which allows for noncoherent decoding when the channel response is not known at the receiver. However, when reliable information on the channel response is available, coherent decoding is preferable for improved performance. Here, we study the relationship between the performance criteria on the diversity and coding advantages provided by unitary space-time codes with noncoherent and coherent decoding. We show that when a unitary space-time code achieves full spatial diversity with noncoherent decoding, full spatial diversity is also guaranteed with coherent decoding.