PPLN 비선형 결정과 이중통과법을 이용한 DOFA 시스템에서 증폭된 연속발진형 파장가변 적외선 레이저광의 제 2고조파 발생

유길상,조재흥,고광훈,임권,정도영,Yoo, Kil-Sang,Jo, Jae-Heung,Ko, Kwang-Hoon,Lim, Gwon,Jeong, Do-Young 한국광학회 2008 한국광학회지 Vol.19 No.3

The optimum conditions of second harmonic generation (SHG) can be successfully achieved experimentally using single pass and double pass methods of a pumping beam. The beam has a power of several Watts radiated by a DOFA (Diode Laser Oscillator & Fiber Amplifier) system, which is a high power CW wavelength tunable infrared laser system, in a PPLN (Periodically Poled MgO doped Lithium Niobate) nonlinear crystal. In the case of a single pass method, the parameters are the wavelength of 535 nm for SHG and the output power of 245 mW generated from the pumping input beam with wavelength of 1070 nm and the power of 2.45 W at phase matching temperature of $108.9^{\circ}C$. The conversion efficiency of SHG was 10%. In order to enhance the output of SHG, the double pass method of the SHG system of a PPLN using a concave mirror for the retroreflection and a pair of wedged flat windows for phase compensation was also presented. In this double pass system, we obtained the SHG output beam with the wavelength of 535 nm and the maximum power of 383 mW at optimum phase matching temperature of $108.5^{\circ}C$ by using an incident pumping beam with wavelength of 1070 nm and the power of 2.45 W. The maximum conversion efficiency is 15.6%, which is more than that of the single pass method.

A Wavelet-Based Video Watermarking Approach Robust to Re-encoding

유길상,이원형,Yoo, Kil-Sang,Lee, Won-Hyung The Korea Institute of Information and Commucation 2008 한국통신학회논문지 Vol.33 No.1C

We present in this paper a method of digital watermarking for video data based on the discrete wavelet transform. In the proposed method, a watermark signal is inserted into the decompressed bitstream while detection is performed using the uncompressed video. This method allows detection if video has been manipulated or its format changed. We embed the watermark in the lowest frequency components of each frame in the un-coded video by using wavelet transform. The watermark can be extracted directly from the decoded video without access to the original video. Experimental results show that the proposed method gives the watermarked video of better quality and is robust against MPEG coding, down sampling and re-encoding to other type of video format such as MPEG4, H.264

외국인고용허가제 시행 3년에 대한 평가

유길상(Kil Sang Yoo) 한국사회정책학회 2007 한국사회정책 Vol.14 No.2

본 연구에 의하면 외국인고용허가제는 송출과정을 투명하고 공정하게 하여 송출비리를 예방하는데 크게 기여한 것으로 나타났다. 입국과정에서 지불한 송출비용이 과거 산업연수생제도 하에서보다 3분 1 정도 감소하였다. 노동생산성을 고려하면 내·외국인근로자 간의 임금차별이 거의 없으며, 임금체불과 인권침해사례도 산업연수생제도에 비해 크게 개선된 것으로 나타났다. 고용허가제는 외국인근로자의 사업장 이탈률이 3.3%에 불과하여 과거 산업연수생의 이탈률 50~60%에 비해 크게 개선된 것으로 나타났다. 그러나 여전히 불법체류자가 19만 명이나 존재하고 있어 불법체류 및 불법취업 근절을 위한 정부의 노력이 미흡하였음을 보여주고 있다. 건설업의 경우 외국인의 고용이 내국인 일자리를 부분적으로 잠식하는 현상이 나타나고 있으며, 임금과 근로조건에도 다소 부정적인 영향을 미치고 있는 것으로 나타났다. 외국인력의 도입이 산업구조조정을 저해하지 않도록 하기 위한 제도적 장치가 현재의 고용허가제에는 없어 제도적 보완이 시급하며, 양질의 외국인력을 도입할 수 있는 선별기능을 강화하는 것도 시급한 것으로 나타났다. This paper shows that Korea`s EPS for foreign labor has improved in transparency and fairness in recruiting migrant workers and their immigration process. The fee for coming into Korea under EPS has reduced to one third compared with former industrial training system. There is almost no wage differential between local and migrant workers considering labor productivity gap. Protecting basic human rights for migrant workers has greatly improved as well. In spite of such a big success, Korea`s EPS leaves something to be developed. About 190 thousand irregular migrant workers, which are almost same number of people just before Korea introduced EPS in 2004, are still working in Korea. This means that Korea has not successfully reduced irregular migrants even after introducing EPS. Migrant workers began to slightly deteriorate wages and working conditions in some industries such as construction sector. There is no systematic instruments for preventing small and medium sized firms that demand low skilled migrant workers from delaying industrial reconstruction by depending on foreign labor. Thus Kora has to develop efficient measures for overcoming those challenges.

한국 실업급여 수급자의 특성

유길상 ( Kil Sang Yoo ) 한국노동연구원 2003 노동정책연구 Vol.3 No.1

정지영상에서 저작권 보호 및 위변조 검출을 위한 하이브리드 디지털 워터마킹 기법

유길상 ( Kil-sang Yoo ),송근실 ( Geun-sil Song ),최혁 ( Hyuk Choi ),이원형 ( Won-hyung Lee ) 한국인터넷정보학회 2003 인터넷정보학회논문지 Vol.4 No.4

Digital image manipulation software is now readily available on personal computers. It is therefore very simple to tamper with any image and make it available to others. Therefore, copyright protection of digital contents and insurance of digital image integrity become major issues. In this paper, we propose a hybrid watermarking method to identify locations of tampered region as well as copyright. Our proposed algorithms embed the PN-sequence into low frequency sub-band of the wavelet transform domain and it doesn`t need the original image in extraction procedure. The experimental results show good robustness against any signal processing with tamper detection on still image.

4차 산업혁명시대의 직업능력개발정책 - 이행노동시장 모형을 중심으로 -

유길상 ( Kil-sang Yoo ) 한국실천공학교육학회 2017 실천공학교육논문지 Vol.9 No.2

The purpose of this paper is to review the effects of the 4th Industrial Revolution on job competency development by the Transitional Labor Market(TLM) model, and suggest job competency development policiy in the rea of the 4th Industrial Revolution. The 4th Industrial Revolution will create new jobs, destroy many current jobs, and will fundamentally change employment pattern, contents of jobs and ways of works. In these circumstances, we will confront more risks in each stage of labor market transition. To minimize the risks of TLM, we should reform education and develop life time career and job competency. We have to train high level talented persons to lead the 4th Industrial Revolution. We have to retrain employed people to adjust new technology and to enhance employability and adaptability. We have to train vulnerable groups so that they may adjust new circumstance. Government should develop life time job competency development open platform.

평생 능력 개발 : 개선된 내일배움카드제훈련에 대한 평가

유길상 ( Kil Sang Yoo ) 한국실천공학교육학회 2012 실천공학교육논문지 Vol.4 No.1

Korean government improved the Individual Training Account (ITA) System in September 15, 2011. This paper evaluated the Improved Individual Training Account System of Korea based on the success conditions of contracting-out public services. The results showed that the improved ITA system of Korea was expected to solve some of the problems of former ITA system of Korea by stabilizing ITA training market, improving target of ITA and better matching between jobs and training courses, and activating trainees. Nevertheless the improved ITA system of Korea still has some problems to be solved. The relationship between job placement services and issue of ITA should be closer by improving tailored total one-stop services for job seekers. The government should develop infrastructure for evaluating, monitoring and supporting the ITA training to enhance the effectiveness and efficiency of the ITA training system.

고용서비스 전달체계의 발전 추세와 시사점 -호주,미국,영국의 사례를 중심으로-

유길상 ( Kil Sang Yoo ) 한국사회보장학회 2006 사회보장연구 Vol.22 No.4

고용보험제도의 조기재취업수당 수급자 특성

유길상 ( Kil Sang Yoo ) 한국사회보장학회 2007 사회보장연구 Vol.23 No.3

고용보험 전달체계 개선방안 -실업급여 수급자에 대한 서비스를 중심으로-

유길상 ( Kil Sang Yoo ) 한국사회보장학회 2010 사회보장연구 Vol.26 No.3

This article develops ideal model of employment insurance delivery system based on benchmark cases in developed countries and literature survey, and evaluates and proposes reforming agenda for Korean employment insurance delivery system. The ideal model of employment insurance delivery system is to identify vulnerable unemployed people who have high probability of long-term unemployment, to identify barriers to employment of each vulnerable unemployed person, to supply individualized and tailored employment services to each unemployed person, and to activate the unemployed. In this point of view, employment insurance delivery system in Korea leaves much to be desired in several respects. This article proposes strategy and methods to reform employment insurance delivery system for Korea.