• Journal of Microbiology and Biotechnology
• /
• v.9 no.3
• /
• pp.346-351
• /
• 1999

Tumor cells may alter the expression of proteins involved in antigen processing and presentation, allowing them to avoid recognition and elimination by cytotoxic T cells. In order to investigate whether the major histocompatibility complex (MHC) class I-mediated antigen processing machinery is preserved in human lung cancer cell lines, we examined the expression of multiple components of the MHC class I antigen processing pathway, including transporter associated with antigen processing (TAP), $\beta_2$-microglobulin, MHC class I molecules, and chaperones which have not been previously examined in this context. Row cytometry analysis showed that the cell surface expression of MHC class I molecules was downregulated in all of the cell lines. While some cell lines showed no detectable expression of MHC class I molecules, pulse-chase experiments showed that MHC class I molecules were synthesized in the other cell lines but not transported from the endoplasmic reticulum to the cell surface. Low or nondetectable levels of TAP1 and/or TAP2 expression were demonstrated by Western blot analysis in all of the cell lines, representing a variety of lung tissue types. In some cases, this was accompanied by loss of tapasin expression. Our findings suggest that downregulation of antigen processing may be one of the strategies used by tumors to escape immune surveillance. This study provides further information for designing the potential therapeutic applications such as immunotherapy and gene therapy against cancers.

• Journal of Sensor Science and Technology
• /
• v.9 no.4
• /
• pp.274-280
• /
• 2000

This paper deals with an experimental study to apply commercial semiconductors to measure radiation dose rate for gamma ray. Since the low cost, small size, high efficiency and ruggedness of silicon photodiodes make them attractive photodetectors, they coulde be effectively used in measuring any radiation such as gamma ray. Most PN photodiodes show that the reverse current increases when the light is increased. Therefore the depletion region of them have influence on the reverse current, so we choose silicon PIN photodiodes with large depletion region. In order to detect radiation dose rate and then, to apply in developing any gamma ray dosimeter, some examinations and experiments were performed to PIN photodiodes in this work. Two kinds of PIN photodiodes, such as NEC's PH302 and SIEMENS's BPW34, were tested in a Co-60 gamma irradiation facility with a semiconductor parameter analyzer. As a result, we found that such PIN photodiodes present good linearity in diode current characteristics with dose rate. Therefore silicon PIN photodiodes could be suitably used in designing gamma ray dosimeters.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.3 no.2
• /
• pp.9-18
• /
• 1999

The seismic over-strength factor Ω is evaluated for 4-story reinforced concrete buildings in Korea, which has low seismic intensity. For this study, the seismic load suggested in' Aseismic guideline research- phase ll' (in Korea) is used. When 3D study-models are designed, span length and bay number are varied and accidental torsional moment is considered. And the models are analyzed by push-over analysis, in which external and internal frame are connected by rigid-link. As a result of numerical experiments, Ω is increased as the bay number or span length is increased. Because, by the including of accidental torsional moment in designing process, the increased ratio of strength of external columns is larger than the increased ratio of span length or bay number. And this makes the failure mode of model closer or strong-column and weak-beam mechanism.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.5
• /
• pp.1221-1230
• /
• 1997

In this study, the performance of a parallel file system(N-PFS), which is inplemented using conventional disks as disk arrays on a Workstation Cluster, is analyzed by using analytical method and adtual values in experiments.N-PFS can be used as high-performance file sever in small-scale server systems and effciently pro-cess massive data I/Os such as multimedia and scientifid data. In this paper, an analytical model was suggested and the correctness of the suggested was verified by analyzing the experimental values on a system.The result of the appropriate stping unit for processing massive data of the Workstation Cluster with 8 disks is 64-128Kbytes and the maximum throughput on it is 15.8 Mbytes/ses.In addition, the performance of parallel file system on massive data is bounded by the time required to copy data between buffers.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.63 no.4
• /
• pp.301-306
• /
• 2014

Recently in accordance with the rapid development of the industrial society, the accidents caused by dielectric breakdown have been increasing in power grid. It is important to prevent the dielectric breakdown of a high voltage apparatus to reduce the damage from electrical hazards. To establish an electrically reliable database of insulation design criteria for high voltage apparatus, a study on dielectric characteristics test is indispensable. In this study, dielectric characteristics according to field utilization factors (${\xi}$) which are represented as the ratio of mean electric field to maximum electric field are investigated. the dielectric breakdown experiments by using several kinds of electrode systems made with stainless steel are performed by AC breakdown voltage under air-insulation. Also, the experimental results are analyzed by the Weibull distribution. As a result, it is found that the dielectric characteristics of air-insulation are determined by ${\xi}$ as well as arrangement of electrode systems. It is considered that the results of this study would be applicable to designing the air-insulated high voltage apparatuses.

• Journal of Power Electronics
• /
• v.6 no.1
• /
• pp.38-44
• /
• 2006

In this paper, a speed sensorless control for an ultrasonic motor (USM) using a neural network (NN) is presented. In the proposed method, rotor speed is estimated by a three-layer NN which adapts nonlinearities associated with load torque and motor temperature into control. The intrinsic properties of a USM, such as high torque for low speeds, high static torque, compact size, etc., offer great advantages for industrial applications. However, the speed property of a USM has strong nonlinear properties associated with motor temperature and load torque, which make accurate speed control difficult. These properties are considered in designing a control method through the application of mathematical models. In these strategies, a detailed speed model of the USM is required which makes actual applications impractical. In the proposed method, a three-layer NN estimates the speed of the USM from the drive frequency, the root mean square value of input voltage and the surface temperature of the USM, where no mechanical speed sensor is needed. The NN speed based estimator enables inclusion of variations in driving conditions due to input signals of the NN involved during the driving state of the USM. The disuse of sensors offers many advantages on both the cost and maintenance front. Moreover, the model free sensorless control method offers practical controller construction within a small number of parameters. To validate the proposed speed sensorless control method for a USM, experiments have been executed under several conditions.

• Journal of the Ergonomics Society of Korea
• /
• v.28 no.4
• /
• pp.51-59
• /
• 2009

These days mobile phone which were used mainly by grown-up persons are now widely used among children as well due to new social demands. Despite this trend, existing mobile phones are still being designed and produced according to the taste of people in their 20s and 30s, even the elderly, not satisfying physical, emotional and cognitive characteristics raised by children. This study aimed to extract the design factors of mobile phones for children by reflecting functional factors requested by children and parents in QFD's customer demands. First, functional and design factors requested in mobile phones for children were extracted from existing products and documentary records and some functional factors were selected through a process of integration and omission. The survey research was conducted on children and parents, based on the selected functional factors. Based on the survey research, functional factors were analyzed using AHP, and key functional factors considered by children and parents in mobile phones for children were investigated. Finally, in order to reflect the results in QFD, the correlation between functional factors and design factors was constructed as HOQ through experts' evaluation. The results showed that both children and parents recognized the basic functions such as telephoning, text messaging and phone directory as high priority functional factors, even though the relative importance was different between children and parents. Therefore, it is likely to satisfy the desires of both children and parents by designing mobile phones for children in consideration of design factors such as menu depth, button independence and button arrangement. It is expected that this study will promote experiments on design factors and propose basic data for and guidelines to mobile phone design for children.

• Journal of Digital Contents Society
• /
• v.5 no.1
• /
• pp.12-21
• /
• 2004

Modem society is information oriented with countless people needing quick reliable information. They also wart to be freed from the limitations of reality such astime and space and experience the world of imagination as if it was reality. Design is creating something out of nothing which has an innate sense of virtual within it. Since it is a process of bringing an imagingnation or an image to life, it can be described as the realization of virtuality. there are many ways in which computer adapted methods were utilized for design up to now. With the advance of computers, the process of desinging became efficient, visually complex and much easier. Undoubtedly, computer is a powerful hardware an design and furthermore, find a way to maximize the presence and to actively incorporate this in designing. The virtual reality system can be widely applied to environmental design to provude a high quality design and enhance the feeling of reality through imitation experiments. Computer simulation such as virtual reality systems is expected to be used widely in environmental design.

• Particle and aerosol research
• /
• v.10 no.4
• /
• pp.137-154
• /
• 2014

Prediction of the behavior of radioactive aerosol particles in a containment is of importance for the assessment of the consequences of nuclear power plant severe accidents because most radioactive air pollutants are emitted as aerosol particles upon severe accident. The performance of engineering safety features (ESFs) is also influenced by the characteristics of the aerosol particles. In this article, the characteristics of aerosol particles in reactor containments reported by previous studies were reviewed. The results of the experiments for postulated accidents in test reactors, for aerosol behavior analysis using artificial test aerosols, and for ESF performance evaluation were summarized. The summary of this article will be of use in designing and performance-evaluating ESFs.

• Journal of Radiation Protection and Research
• /
• v.28 no.2
• /
• pp.79-85
• /
• 2003

This study was intended to estimate Hp(10) recommended by the ICRU using the $CaSO_4:Dy,P$ element developed in the KAERI. For the estimation of Hp(10), TL response should be compensated properly through the energy range using filter materials since $CaSO_4:Dy,P$ is of severe photon energy dependent response. Various experiments and computations using Monte Carlo Code were carried out for designing filter satisfying the performance requirements of the ISO related to TL dosimeter. Under the completed filter, the relative response of $CaSO_4:Dy,P$ showed $0.75{\sim}1.0$ for photons in the range of $20{\sim}662keV$. Especially it was possible to reduce the thickness of front filter and simplify the filter combination with rear filter of larger diameter and to considerably improve angular dependence by introducing taper to the filler.