• The KIPS Transactions:PartD
• /
• v.10D no.2
• /
• pp.317-326
• /
• 2003

The possession rate of residential telephones tend to decrease as mobile phones are widely spread. There is also a decrease in the access rate of the qualified respondents due to the low rate of phone book registration and that of house owner's presence at home. Such a change in telephone survey environment calls for another survey-channel which makes good use of new telecommunication services. In this paper, a mobile survey system was designed and performed by the use of SMS (Short Message Service) which is a kind of mobile data communication service. The system draws the sample by using random digit sampling based on 'quota allocation', and sends the SMS to the sample according to the arranged scheduler. Then, the survey-panel which received the SMS connects to the responding server by pressing the 'send' button (which is connected by the callback number), responding to the question. As a result, the responding value is stored in the database and is analyzed in real-time. This system is distinguished from other research methodologies for its simplicity in data collection, its inexpensive research price, and the innovatively low research time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.11a
• /
• pp.163-166
• /
• 2004

모바일향 90nm DRAM을 개발하기 위하여 비대칭 채널 구조를 갖는 Recess Channel Array Transistor (RCAT)로 cell transistor를 구현하였다. DRAM cell transistor에서 junction leakage current 증가는 DRAM retention time 열화에 심각한 영향을 미치는 요인으로 알려져 있으며, DRAM의 minimum feature size가 점점 감소함에 따라 short channel effect의 영향으로 junction leakage current는 더욱 더 증가하게 된다. 본 실험에서는 short channel effect의 영향에 의한 junction leakage current를 감소시키기 위하여 Recess Channel Array Transistor를 도입하였고, cell transistor의 채널 영역을 비대칭으로 형성하여 data retention time을 증가시켰다. 비대칭 채널 구조을 이용하여 Recess Channel Array Transistor를 구현한 결과, sub-threshold 특성과 문턱전압, Body effect, 그리고, GIDL 특성에는 큰 유의차가 보이지 않았고, I-V특성인 드레인 포화전류(IDS)는 대칭 채널 구조인 transistor 대비 24.8% 정도 증가하였다. 그리고, data retention time은 2배 정도 증가하였다. 본 실험에서 얻은 결과는 향후 저전압 DRAM 개발과 응용에 상당한 기여를 할 것으로 기대된다.

• KDI Journal of Economic Policy
• /
• v.29 no.3
• /
• pp.75-109
• /
• 2007

This paper empirically investigates the effects of import tariff on within-plant productivity growth in Korean manufacturing, using the detailed plant-level longitudinal data of the Korea Census of Manufacturers for the period of 1993-2003. Our main findings are as follows: First, the productivity changes of Korean manufacturing for the period under analysis were mostly induced by within-plant productivity gains, rather than within-industry and/or between-industry resource reallocations. Second, after controlling for firm-specific heterogeneity, the estimation results indicate that lowering tariff-barriers has a positive impact on within-plant TFP growth. We interpret the results in a way that trade liberalization through the removal of tariff and non-tariff barriers heightens the competitive pressure, which in turn creates incentives to reduce production and managerial inefficiency and to invest more on innovative activities. Third, we also find that plant productivity growth from reducing tariff barriers is particularly conspicuous within a year after tariff changes, which implies that plants are quickly adjusting to heightened import competition. On the other hand, our results show that the trade effect on employment creation proceeds relatively slow.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.2
• /
• pp.136-140
• /
• 2014

This paper introduces a multi-touch recognition and tracking method for self capacitive TSP(Touch Screen Pannel). Self capacitive TSP recognizes finger touches by sensing capacitive change of ITO transparent conducting film arranged by rows and columns on the TSP pannel. They have some advantages such as high SNR, fast sensing, and simple touch processing, but have very difficulties for multi-touch processing. This disadvantage makes that the mutual capacitive TSPs, which have no such disadvantage, have been more widely used especially for multi-touch applications. However, since the other applications for remote control pad or recently developed wearable devises have only restrictive requirements for multi-touch, the disadvantage of self capacitive TSP is not a critical problem. In this paper, we first describe multi-touch recognition problems in self capacitive TSP and then propose how to overcome those problems and a tracking method of two touches when they are moving. Experimental results of our method showed that our algorithm works well in two touches.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.5
• /
• pp.1123-1131
• /
• 2005

In this paper, optimal position of optical phase conjugator (OPC) for best compensating distorted WDM channels due to both chromatic dispersion and self phase modulation (SPM) in $8{\times}40$ Gbps WDM systems is numerically investigated, and the eye opening penalty (EOP) and bit error rate (BER) characteristics of overall WDM channels at this position is investigated, comparing with that in case of OPC placed at mid-way of total transmission length. It is confirmed that the compensation extents in WDM system with OPC is more improved by the shifting OPC position from the mid-way of total transmission length, depending on the modulation format and fiber dispersion coefficient. Ant it is confirmed that, from a viewpoint of the reception performance, EOP of each channel is more or less different with one another, but the BER characteristics of overall channels are almost equal.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.08a
• /
• pp.165-165
• /
• 2010

GaInZnO는 투명 비정질 산화물 반도체로서 태양전지, 평판 액정 디스플레이, 잡음방지 코팅, 터치 디스플레이 패널, 히터, 광학 코팅 등 여러 응용에 쓰인다. 이 논문에서는 투명전자소자로 관심을 모으고 있는 GaInZnO의 전자적 그리고 전기적 특성을 측정하였다. GaInZnO 박막은 $SiO_2$ (100)/Si 기판위에 RF 마그네트론 스퍼터링 증착법으로 $Ga_2O_3:In_2O_3:ZnO$의 조성이 2:2:1로 된 타겟을 가지고 박막을 성장시켰다. 성장한 후에 RTP를 이용하여 30분간 열처리 하였다. GaInZnO의 전자적 특성을 나타내는 띠틈 및 실리콘 기판과의 원자가 띠 오프셋 값을 측정하였으며, 이 값들을 통해 GaInZnO박막과 실리콘 기판과의 띠 정렬도 수행하였다. 띠틈은 반사 전자 에너지 손실 분광법(REELS)을 이용하여 측정하였고, 원자가 띠 오프셋은 광전자 분광법(XPS)을 이용하여 측정하였다. 열처리 온도가 $400^{\circ}C$까지는 띠틈의 변화 및 XPS 결합에너지의 변화가 없는 것으로 보아 열적안정성이 우수함을 알 수 있다. 반면 $450^{\circ}C$에서의 띠틈이 감소하는 것으로 보아 $450^{\circ}C$에서는 열적안정성이 깨지는 것을 알 수 있다. GaInZnO 박막을 채널 층으로 하고 전극은 알루미늄(Al)으로 된 TFT를 제작하여 전기적 특성을 조사하였다. TFT 특성 결과 이동도가 약, subthreshold swing(S.S)이 약 1.5 V/decade, 점멸비가 약 $10^7$으로 측정되었다. 유리 위에 증착시킨 GaInZnO 박막의 투과율을 측정해본 결과 모든 시료가 가시광선 영역에서 80%이상의 투과율을 갖는 것으로 보아 투명전극소자로 응용이 가능하다는 것을 알 수 있었다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.12
• /
• pp.1591-1597
• /
• 2012

Adherend samples were made from unsaturated polyester and woven and mat glass fibers by the hand layup and vacuum methods. The mechanical properties of the adhesive, composite adherends, and terminal-joint and secondary-joint specimens were determined experimentally. Combinations of the experiment results and the bonding theory were used in this study. The maximum and average shear stresses were calculated based on the maximum tensile force and geometry parameters of the joint specimens. The results of the maximum and average shear stresses were compared and evaluated for six joints. The results showed that the grinding and grind/acetone joint had the highest strength among three types of terminal-joints. Similarly, the mat-mat and mat-woven joints had the highest strength among three types of secondary-joints with the same value. Conversely, no treatment and woven-woven bonding had very low strength. In each case, failure occurred always at two ends and then moved toward the middle area of the overlap length.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.100-100
• /
• 2011

2004년 일본의 Hosono 그룹에 의해 처음 발표된 이래로, amorphous gallium-indium-zinc oxide (a-GIZO) thin film transistors (TFTs)는 높은 이동도와 뛰어난 전기적, 광학적 특성에 의해 큰 주목을 받고 있다. 또한 넓은 밴드갭을 가지므로 가시광 영역에서 투명한 특성을 보이고, 플라스틱 기판 위에서 구부러지는 성질에 의해 플랫 패널 디스플레이나 능동 유기 발광 소자(AM-OLED), 투명 디스플레이에 응용될 뿐만 아니라, 일반적인 Poly-Si TFT에 비해 백플레인의 대면적화에 유리하다는 장점이 있다. 최근에는 Y2O3나 ZrO2 등의 high-k 물질을 gate insulator로 이용하여 높은 캐패시턴스를 유지함과 동시에 낮은 구동 전압과 빠른 스위칭 특성을 가지는 a-GIZO TFT의 연구 결과가 보고되었다. 하지만 투명 디스플레이 소자 제작을 위해 플라스틱이나 유리 기판을 사용할 경우, 기판 특성상 공정 온도에 제약이 따르고(약 $300^{\circ}C$ 이하), 이를 극복하기 위한 부가적인 기술이 필수적이다. 본 연구에서는 p-type Si을 back gate로 하는 Inverted-staggered 구조의 a-GIZO TFT소자를 제작 하였다. p-type Si (100) 기판위에 RF magnetron sputtering을 이용하여 Gate insulator를 증착하고, 같은 방법으로 채널층인 a-GIZO를 70 nm 증착하였다. a-GIZO를 증착하기 위한 sputtering 조건으로는 100W의 RF power와 6 mTorr의 working pressure, 30 sccm Ar 분위기에서 증착하였다. 소스/드레인 전극은 e-beam evaporation을 이용하여 Al을 150 nm 증착하였다. 채널 폭은 80 um 이고, 채널 길이는 각각 20 um, 10 um, 5 um, 2 um이다. 마지막으로 Furnace를 이용하여 N2 분위기에서 $500^{\circ}C$로 30분간 후속 열처리를 실시한 후에, 전기적 특성을 분석하였다.

• Archives of design research
• /
• v.11 no.1
• /
• pp.245-258
• /
• 1998

Due to the information technology improvement and the changing life style, a home is getting a new role of workspace besides the main function as rest area for the family members. Therefore, a demand for the home workstation furniture is increasing nowadays. In this study, three types of workstation furniture id designed, that makes possible the effective works and reflects the characteristics of the house. 1. Panel-based system furniture : main concept is flexibility and expandability, and various units can be composed as desired. 2. Cabinet-type workstation : all functions needed for the home office work is concentrated in a piece of furniture. 3. Movable multi-purpose furniture : small-sized, mobile furniture that functions as a simple workstation or a side station. Home office has a great possibility as a work place for the future, and there is a continuous need for the furniture design with diverse form and function.

• Journal of the Korean Data and Information Science Society
• /
• v.26 no.6
• /
• pp.1271-1281
• /
• 2015

Competing risk analysis is widely applied to analyze a failure time with more than two causes. This paper discusses the application of a competing risk model to a economic activity state of workers with occupational injuries. In particular, main interest is to estimate the distribution of restarting time two kinds of economic activities, (i) returning to original working place and (ii) finding a new job. In this paper, we applied a cumulative incidence function to evaluate their patterns under several individual factors and working place's factor. Furthermore, a subdistributional regression model is applied to estimate the effect of these factors on the returning time. According to result, worker with higher education, younger age and longer working period had a higher chance to return an original working place while one with more severe injuries and skilled laborer had longer returning time to an original working place.