• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2000.11a
• /
• pp.11-11
• /
• 2000

이동통신기술의 급격한 발달로 고주파회로의 packaging과 interconnect 기술의 고성능화 와 저가격화에 대한 새로운 도전이 요구되고 있다‘ 대부분 기존의 무선통신 부품은 P PCB(Printed Wiring Board)기술을 활용하고 있으나 이러한 기술이 점차로 고주파화되는 경 향을 만족시킬수 없어 새로운 고주파 부품기술이 요구되고 있는 실정이다 .. RF 회로를 구성 하기 위하여 PCB소재의 환경적, 치수안정성 문제를 극복하기 위하여 L TCC(Low T Temperature Cofired Ceramics)기술이 최근 주목을 받고 있다. 차세대 이동통신 기술은 수십 GHz 이상의 고주파특성이 우수하고, 고성능의 초소형의 부품을 저가격으로 제조할수 있으며, 시장의 변화에 기민하게 대처할수 있는 기술이 요구되 고 있으며, 이러한 기술적 필요성에 부합할수 있도록 LTCC 기술이 제안되었다. 이러한 C Ceramic Interconnect 기술은 높은 신뢰성을 바탕으로 fine patterning 기술과 저가의 m metallizing 기술로 가능하게 되었다. 초고주파 통신부품기술은 미국과 유럽 등을 중심으로 G GHz 대역또는 mm wave 대역의 기술에 대하여 치열한 기술개발 경쟁을 벌이고 있으며, 이 러한 고주파 패키징 기술을 바탕으로 미래의 군사, 항공, 우주 및 이동통신 기술에 지대한 영향을 미칠수 있는 기반기술로 자리잡을 전망이다. L LTCC 기술은 기존의 후막혼성기술에 비하여 공정이 단순하고 대량생산이 가능하고 가 격이 비교적 저렴하다. 또한 다층구조로 제작할수 있고, 수동소자를 내장할수 있어 회로의 소형화와 고밀도화가 가능하다. 특히 무선으로 초고속 정보를 처리하기 위하여 이동통신기 기의 고주파화가 빠르게 진행됨에 따라서 고분자재료에 비하여 고주파특성이 우수할뿐아니 라 환경적, 치수안정성이 우수한 세라믹소재플 사용함으로써 고주파 손실율을 저감할 수 있 다 .. LTCC 기술은 후막회로 기술과 tape dielectric 기술이 결합된 기술이다. 표준화된 소재 와 공정기술을 활용하여 저가격으로 고성능소자플 제작할 수 있으며, 전극재료로서 높은 전 도도를 갖고 있는 Ag, Cu, Au 및 Pd! Ag릎 사용함으로써 고주파 손실을 저감시킬 수 있다. L LTCC 기술이 최종적으로 소형화, 고기능 고주파 부품기술로 지속적으로 발전하기 위하여 무수축(Zero shrinkage) 소성기술, 광식각 후막기술 등이 원천기술로서 확립될 수 있어야 하 며, 특히 국내의 이동통신 기술에 대한 막대한 투자에도 불구하고 차세대 이동통신 부품기 술에 대한 개발은 상대적으로 미흡한 실정이므로 국내에 LTCC 관련 소재공정 및 부품소자 기술에 대한 개발투자가 시급히 이루워져야 할 것으로 판단된다. 본 발표에서는 지금까지 국내외 LTCC 기술의 발전과정을 정리하였고, 현재 이 기술의 응용과 소재와 공정을 중심으로한 개발현황에 대하여 조사하였으며, 앞으로 LTCC가 발전 해야할 방향을 제시하고자 한다.

• Journal of Radiation Protection and Research
• /
• v.14 no.2
• /
• pp.10-17
• /
• 1989

A study for the assessment of dose given by outdoor radon to respiratory system has been carried out by making use of radon-cups containing CR-39 plastic track detectors. Detection efficiencies were determined by irradiation of the radon-cups in a standard radon chamber of known concentration. Thus determined detection factors of CR-39 plastic track detector in bare, open cup and filtered cup geometry are found to be 0.273, 0.0813 and 0.0371 $trmm^{-2}$/(37$Bqm^{-3}{\cdot}d$), respectively, which are chemically etched in 30% NaOH solution of $70^{\circ}C$ for 220 minutes. The outdoor radon concentrations measured at Taejeon(Chungnam National University) from May 1988 to March 1989 are in the range of 27.4 - 135.8 Bq/$m^3$(0.74 - 3.67pCi/l)by open cup and 16.7 - 143.9 Bq/$m^3$(0.45 - 3.89 pCi/l) by filtered cup, which yield overall annual average value of outdoor radon concentration of $70.8Bq/m^3$(1.91 pCi/l). Corresponding effective dose equivalent rate to respiratory system of ICRP standard man is assessed to be 520 nSv /h.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.4
• /
• pp.659-666
• /
• 2006

Servo-motors are used as key components of automated system by performing precise motion control as accurate positioning and accurate speed regulation in response to the commands from computers and sensors. Especially, the linear brushless servo-motors have numerous advantages over the rotary servo motors which have connection with the friction induced transfer mechanism such as ball screws, timing belts, rack/pinion. This paper proposes an estimation method of unknown motor system parameters using the informations from the sinusoidal driving type linear brushless DC motor dynamics and outputs. The estimated parameters can be used to tune the controller gain and a disturbance observer. In order to meet this purpose high performance Digital Signal Processor, TMS320F240, designed originally for implementation of a Field Oriented Control(FOC) technology is adopted as a controller of the liner BLDC servo motor. Having A/D converters, PWM generators, rich I/O port internally, this servo motor application specific DSP play an important role in servo motor controller. This linear BLDC servo motor system also contains IPM(Intelligent Power Module) driver and hail sensor type current sensor module, photocoupler module for isolation of gate signals and fault signals.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.6
• /
• pp.526-534
• /
• 2011

The MFS (Mlti-Functional Structure) concept, which integrates the electronics, thermal control and structure into a single packaging system, has been developed and applied to reduce the volume and weight of the satellite. Therefore, this MFS can eliminate the bulky chassis/frames, cables and connectors of the electronic equipment. The main point of this traditional MFS is the replacement of the electrical chassis/frames with MCMs (Multi-Chip Modules) that require much costs and efforts for developing. This paper shows the new MFS concept that effectively saves the volume and weight. The structure including the thermal control and radiation shielding elements will be designed and manufactured as the rectangular grid-stiffened structure. The rectangular grid-stiffened structure is the modification of the iso-grid structure, and provides the enough spaces for putting the general PCBs without the chassis/frames.

• Journal of the Korean Wood Science and Technology
• /
• v.35 no.6
• /
• pp.100-107
• /
• 2007

People have spent lots of time inside building about 90% of these day. Industry has been developed rapidly after I960. Construction materials had changed from natural materials to chemical materials and confidentiality of building has been more higher than before by policy of saving energy. These have caused sick-building syndrome (SBS) for us. So people want environmental construction materials for their house. We designed a environmental loess (yellow soil) finishing material which was composed of loess, water, water-soluble resin, hardener and filler. The purposes of this study were that making an environmental loess finishing material with optimum ratio, evaluating the usability of loess finishing material for wall. Furthermore it was suitable for wall to evaluate mechanical properties that are impact test, cracking test, abrasion test and de-bonding test, environmental properties that were emission of VOCs, formaldehyde and far infrared radiation.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.19 no.2
• /
• pp.85-91
• /
• 1983

The behaviour of shrimp in response to the trap was much influenced by the type, size and the dimensions of entrance as well as physiological and ecological conditions. The entry and the escape behaviour of shrimp to the model trap were observed in accordance with netting materials, baits, type and slope of entrance, and gathering response were also investigated on the odour of bait extracts in the aquarium from June to August, 1983. Entering shrimp to the circular entrance was significantly more than to the triangular or the square; however, no differences were found in the entry behacior among netting materials i e., P. A, P. E. and cotton. According as the slope of entrance was increased its angle from 0$^{\circ}$ to 90$^{\circ}$, number of entering shrimp was decreased; however, number of escaping shrimp at 30$^{\circ}$or 60$^{\circ}$ with time was fewer than at 0$^{\circ}$ or 90$^{\circ}$. Gathering responses of shrimp on the odours were more sensitive to the flesh of mackerel or the shrimp than to the pickled anchovy, or the pettitioes, while no differences were found between another bait extracts, i e., the shrimp and the flesh of mackerel, the short-necked clam and the horse mackerel, the flesh and the viscera of mackerel.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.20 no.6
• /
• pp.501-508
• /
• 1987

Gonadal development, the annual reproductive cycle and the first sexual maturity of hen clam, Mactra chinensis were studied histologically. Sexuality of the species was dioecious. The gonads were irregularly arranged from the subregion of mid-intestinal 91an4 in visceral cavity to the reticular connective tissue of the foot. The ripe eggs were about $50-60\;{\mu}m$ in diameter, and they were surrounded by gelatinous membrane. The spawning period was from May to September when the water temperature ranged $18.5-27.0^{\circ}C$, with the peak in June and July. The annual reproductive cycle of Mactra chinensis could be classified into five successive stages; multiplicative, growing, mature, spent, and degenerative and resting. The monthly changes of the fatness coefficient closely correlated with the annual reproductive cycle. Percentages of the first sexual maturity of female and male clams were over $50\%$ among those individuals ranging from 3.5 to 3.9cm, and $100\%$ in those over 5.0cm in shell length.

• Journal of the Microelectronics and Packaging Society
• /
• v.9 no.3
• /
• pp.19-23
• /
• 2002

This paper presents a micro fluxgate magnetic sensor in printed circuit board (PCB). In order to observe the effect of the closed magnetic path, the magnetic cores of rectangular-ring and two bars were each fabricated. Each fluxgate sensor consists of five PCB stack layers including one layer magnetic core and four layers of excitation and pick-up coils. The center layer as a magnetic core is made of a Co-based amorphous magnetic ribbon with extremely high DC permeability of ~100,000. Four outer layers as an excitation and pick-up coils have a planar solenoid and are made of copper foil. In case of the fluxgate sensor having the rectangular-ring shaped core, excellent linear response over the range of -100 $\mu$T to ＋ 100 $\mu$T is obtained with 540 V/Tsensitivity at excitation square wave of 3 $V_{p-p}$ and 360 KHz. The chip size of the fabricated sensing element is $7.3 \times 5.7\textrm{mm}^2$. The very low power consumption of ~8 mW was measured. This magnetic sensor is very useful for various applications such as: portable navigation systems, telematics, VR game and so on.n.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.6
• /
• pp.126-134
• /
• 2015

A sleep disorder is being recognized as one of the major health issues related to high levels of stress. At the same time, interests about quality of sleep are rapidly increasing. However, diagnosing sleep disorder is not a simple task because patients should undergo polysomnography test, which requires a long time and high cost. To solve this problem, an accelerometer embedded wrist-worn device is being considered as a simple and low cost solution. However, conventional methods determine a state of user to "sleep" or "wake" according to whether values of individual section's accelerometer data exceed a certain threshold or not. As a result, a high miss-classification rate is observed due to user's intermittent movements while sleeping and tiny movements while awake. In this paper, we propose a novel method that resolves the above problems by employing a dynamic classifier which evaluates a similarity between the neighboring data scores obtained from SVM classifier. A performance of the proposed method is evaluated using 50 data sets and its superiority is verified by achieving 88.9% accuracy, 88.9% sensitivity, and 88.5% specificity.

• The KIPS Transactions:PartB
• /
• v.14B no.5
• /
• pp.329-336
• /
• 2007

In this paper we propose both the construction of image DB including information on the shooting location and direction of the captured outdoor images and the efficient retrieval method from the DB. Furthermore, for the automatic extraction of the location and direction information, we suggest to have the Digital Camera equipped with an expandable GPS modulo which has a function to calculate the location and direction and also to utilize GPS IFD tags in the EXIF. Then that will make it possible for us to retrieve quickly and precisely the target image with its geography and other objects on the ground included. In the previous retrieval method based only on the location, we eel some extra useless images due to the fact that all the images in the ROI(Region Of Interest) are searched on one condition, radius. However, with the proposed method in this paper, we can not only retrieve all the images selectively within the ROI but also achieve nearly 100% of precision when we search for the target images within DOI(Direction Of Interest) with another condition, direction, added. Applying this method to an image retrieval system, we can classify or retrieve natural images based on the location and direction information, which, in turn, will be vitally useful to diverse industrial fields such as disaster alarm system, fire and disaster prevention system, traffic information system, and so forth.