• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.10 s.175
• /
• pp.144-149
• /
• 2005

This study presents the method of extracting shape design data on any aspheric lens by reverse engineering. The design formula fur aspheric lenses is needed in almost all of the design, manufacture and measuring processes. The difficulty in designing the lens lies in the fact that it uses a complex formula for the aspheric surface, and many of the preliminary design values must be selected before actually inserting them into the formula. If the values could be extracted from an aspheric lens for which the structural design information is unknown and used in designing other lenses of similar characteristics, the difficulties in designing and measuring aspheric lens could be reduced. Therefore, in this study, the concept of reverse engineering was applied to demonstrate the method of extracting shape design information of aspheric lens from an arbitrary aspheric lens.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.10
• /
• pp.191-198
• /
• 2003

In this study, aberration free aspherical lens design method named ray reverse tracing method is introduced. Differently from the traditional design method, the ray reverse tracing method traces the shape and location of a real object by use of its virtual image. From the result, especially spherical aberration free aspherical lens could be designed by use of the ray reverse tracing method. Furthermore, it could reduce the degree of dependence of optical characteristics on designer's ability, because deformation terms and optimization can be eliminated, which has been performed in conventional lens design process.

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.10c
• /
• pp.451-453
• /
• 2002

정보화 시대를 맞이하여 정보 인프라의 확충과 이를 기반으로 한 다양한 비즈니스 모델이 출현하면서, 인터넷 비지니스는 우리 산업의 중심으로 확산되고 있다. 이에 따라 개인과 개인, 기업과 기업, 기업과 개인간에 새로운 커뮤니케이션 수단으로 부상한 전자메일은 이제 우리 사회를 윤택하게 만드는 필수도구로 자리잡았다. 더군다나 전자메일은 그 파급효과나 비용절감의 측면에서 수많은 인터넷기업의 마케팅 수단으로써 범용적으로 활용되고 있다. 그러나 최근들어 불법 스팸메일과 유해성 메일이 급증하면서 전자메일 환경이 급속도로 악화되고 있어 그 위험수위가 극에 달해 있다. 이러한 불법 스팸메일은 전자메일 마케팅에 대한 신뢰도를 하락시켜 기업 활동을 위축시키고 있으며 유해성 메일에 무방비로 노출되어 있는 청소년 보호와 인터넷상의 개인정보보호 차원에서도 반드시 척결되어야할 “공공의 적”이라는 인식이 확산되고 있다. 하지만 최근 인터넷상의 공개된 전자메일 주소를 수집, 가공하여 스팸메일을 대량으로 발송할 수 있는 자동화된 프로그램의 개발로 인하여 스팸메일을 더욱 증가하고 있는 추세이다. 이 논문에서는 이러한 문제정점을 인식하고 자동화되어있는 전자메일 추출 프로그램으로부터 전자메일 주소를 보호할 수 있는 방안을 제시한다.

• Journal of Korea Water Resources Association
• /
• v.33 no.6
• /
• pp.689-699
• /
• 2000

This paper presents the integrated storage function model (ISFM) to improve the accuracy of the storage function model (SFM) which is widely employed for flood runoff analysis and its forecasting in Korea. In order to achieve this objective, the optimization method is applied for estimation of parameters of the model which dominate the accuracy of the analysis, which is usually taken by empirical formulae, and they are treated as time dependent variables. The fuzzy control technique is used to detennine the time variant parameters. In addition, the ISFM can be applied to the combined routing of the watershed and the channel with a residual watershed.ershed.

• Journal of Korea Water Resources Association
• /
• v.33 no.6
• /
• pp.701-709
• /
• 2000

Integrated storage function model (ISFM) is applied to some rainfall-runoff events of the selected basins in Korea to show validity of the proposed model. Comparing the numerical results of the model with the field measurements, the simulated hydrographs and peak flood discharges for the most part showed good agreements, except the occurrence time of the peak discharges which showed a bit discrepancy, and they showed it was very hard to have a sufficient lead-time to forecast the flood when the upstream inflow of the channel reach was more dominant than the inflow from the residual watershed of the channel.hannel.

• Korean Journal of Pharmacognosy
• /
• v.34 no.2 s.133
• /
• pp.145-149
• /
• 2003

Many chemotherapeutic drugs were developed and contributed to the increase of cure rate of cancer, however severe side effect of these drugs is a major cause of poor quality of life of cancer patients. Effect of deer blood on cancer therapy was investigated in mouse tumor model. Deer blood itself was shown to have mild antitumor activity. However it has significant effect on the reduction of the side effects of chemotherapy. Deer blood recovered the reduction of WBC and platelet (myelotoxicity) during fluorouracil chemotherapy. Deer blood also recovered the increase of serum blood urea nitrogen (BUN; indicator of renal toxicity) and increase of serum amylase activity (AMY; indicator of pancreatic toxicity) almost to the control level during cisplatin chemotherapy. Fluorouracil and cisplatin are major chemotherapeutic drugs which are currently used in clinical cancer therapy, and the results strongly suggest that deer blood can be used for reducing the side effects and improving the quality of life during chemotherapy of cancer patients.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1422-1425
• /
• 2003

In the design of optical system, important variables of optical system (including indices, shapes, spaces, stops. etc.) must manipulate in order to balance out offensive aberration. In this paper, it carried out a basic study on the design of micro optical system usable for the acquaintance of visual information in the particular conditions such as capsule type endoscopes. In this study, specification for design of optical system selected voluntarily and the basic design of optical system carried out by using the ray tracing method on the assumption that ideal lenses without aberrations. In the designed optical system, the optimization including aberration correction and the performance evaluation of optical system carried out by using the CODE-V. The final designed optical system consists of seven sheets of lenses. Also the results of performance evaluation. the micro optical system combined with aspherical lenses was confirmed to have improved optical performance as compared with the micro optical system consisted of spherical lenses.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.1
• /
• pp.19-28
• /
• 2020

The spacer, which is located between the bucket and the arm of an excavator, has a role in preventing damage to the excavator arm during excavation work. When the durability of the spacer is increased, the lifetime of the arm can be extended and the processing costs can be reduced. To increase the durability of the spacer, tungsten carbide (WC) coating was applied on the surface of a spacer using the plasma transferred arc (PTA) process. The confirm the durability, a wear test using a pin-on disk type of wear testing machine was done under the given conditions and the wear amount on the surface of a tested specimen was measured using reflective digital holography. The results were compared with that of ALPHA-STEP.

• Journal of Digital Contents Society
• /
• v.19 no.4
• /
• pp.605-613
• /
• 2018

In this paper, we propose a system to walk around the world with virtual reality technology. Although the virtual reality users are interested in the virtual travel contents, the conventional virtual travel contents have limited space for experiencing and lack of interactivity. In order to solve the problem of lack of realism and limited space, which is a disadvantage of existing contents, this system created a virtual space using Google Street View image. Users can have realistic experience with real street images, and travel a vast area of the world provided by Google Street View image. Also, a virtual reality headset and a treadmill equipment are used so that the user can actually walk in the virtual space, which maxmizes user interactivity and immersion. We expect this system contributes to the leisure activities of virtual reality users by allowing natural walking trip from famous tourist spots to even mountain roads and alleys.

• Journal of the Korea Computer Graphics Society
• /
• v.24 no.3
• /
• pp.93-100
• /
• 2018

This paper proposes a small-scale rehabilitation system that allows stroke patients to perform daily rehabilitation training in a virtual home. Stroke patients have limited activities of daily living due to paralysis, and there are many rehabilitation exercises for them to reproduce activities that take place in the house, such as turning lights on and off, door opening and closing, gas valve locking. In this paper, we have implemented a virtual home with the above mentioned daily rehabilitation training elements, by using virtual reality technology. We use Leap Motion, a hand motion recognition device, for rehabilitation of hands and fingers. It is expected that stroke patients can rehabilitate small muscles without having to visit the clinic with uncomfortable body, and will be able to get interesting rehabilitation training by avoiding monotony of existing rehabilitation tools.