• 한국항해항만학회지
• /
• 제42권2호
• /
• pp.87-96
• /
• 2018

A trajectory control system plays an important role in controlling motions of marine vehicle when a series of way points or a path is given. In this paper, a sliding mode control (SMC)-based trajectory tracking controller for marine vehicles is presented. A small-sized unmanned ship is considered as a control object. Both speed and heading angle of a ship should be controlled for tracking control. The common point of related researches was to separate ship's speed and heading angle in control methods. In this research, a new control law from a general sliding mode theory that can be applied to MIMO (multi input multi output) system is derived and both speed and heading angle of a ship can be controlled simultaneously. The propulsion force and rudder force are also applied in modeling stage to achieve accurate simulation. Disturbance induced by wind is also tackled in the dynamics considering robustness of the proposed control scheme. In the simulation, we employed a way-point method to generate ship's trajectory and applied the proposed control scheme to ship's trajectory tracking control. Our results confirmed that the tracking error was converged to zero, thus demonstrating the effectiveness of the proposed method.

• International Journal of Automotive Technology
• /
• 제7권1호
• /
• pp.17-23
• /
• 2006

An experimental study was carried out to obtain the fundamental data about the effect of sub-chamber on pre-mixture combustion. A eve (constant volume combustor) divided into a sub-chamber and a main chamber was used in this experiment. The volume of the sub-chamber was varid trom $0.45\%$ to $1.4\%$ about the whole combustion chamber. The sub-chamber has twelve narrow radial passage holes and a spark plug to ignite the pre-mixture. As the ignition occurs in the sub-chamber by a spark discharge, burned and unburned gas including a great number of radicals is injected into the main chamber, then the multi-point ignition occurs in the main chamber. The combustion pressure is measured to calculate the burning velocity mainly as a function of the sub-chamber volume, the diameter of the passage holes, and the equivalence ratio. In the case of RI (radical ignition) methods, the overall burning time became very short and the maximum burning pressure was slightly increased as compared with that of SI (spark ignition) method. The optimum design value of the sub-chamber is near 0.11 $cm^{-l}$ in the ratio of total area of holes to the sub-chamber volume.

• The Journal of Korean Physical Therapy
• /
• 제6권1호
• /
• pp.171-183
• /
• 1994

Purphose. This present study examines the effect of brief, intense transcutaneous electrical nerve stimulation(BTENS) on sensory nerve conduction, electrical pain threshold, and two-point discrimination measured at the superficial radial nevre distribution in 20 healthy subjects. Subjects. Twenty volunteercs, (10 females and 10 males(age range : 20-38 years : $mean{\pm}SD\;:\;27.00{\pm}5.12$), only subjects without prior traumatological and pathological were eligible to participated in this study. Methods. Nerve conduction were determined for the right superficial radial nerve. Electrical pain threshold were determined for the right wrist ipsilateral to the site of BTENS. Small disc electrodes were attached to the surface of the skin stradding the end of the radius. Square wave electrical pulses were delivered from an isolated stimulator through a constant current device at a frequency of 2 Hz(5 ms pulse width). Two-point discrimination, measured on the sensory distribution of superficial radial nerve. BTENS was delivered using a Max-SD( Medical design co.) portable battery powered stimulator. A cicular Ag/AgCl electrode in contact with hypertonic saline gel was attached to the lateral(radial side) surface of the forearm. Results. No significant effects were observed between stimulation methods in the prestimulation cycle(multi-way ANOVA repeated measures : distal latency ; F1.14=0.332. amplitude ; F 0.80=0.445, pain threshold ; F0.06=0.940.2 point discrimination ; F1.50=0.236). Highly significant effects were observed time with the pretreatment and 6 posttreatment cycles(p<0.01). Mighty significants differences in nerve conduction and pain threshold were found using un multi-way ANOVA repeated measures among stimulation methods for each cycles(p<0.01). Conclusion and Discussion The authors concludes that both nerve conduction and pain threshold changes are associated with therapy (stimulation) level of BTENS.

• 한국정보통신학회논문지
• /
• 제6권1호
• /
• pp.6-13
• /
• 2002

본 논문은 선형 행렬 부등식 (LMI) 기법을 이용하여, 도립진자 시스템의 안정화 조절 제어 및 추종 제어 특성을 만족하는 다목적 제어기를 선계하기 위하여, 도립진자의 모델을 복수개의 모델을 원소로 가진 폴리토프 모델(polytopic model)로 표현하고, 극점 배치 Η$_2$/Η$_{\infty}$ 제어기를 설계하는 과정을 예시한 것이다. 도립진자의 진폭이 비교적 큰 경우, 하나의 동작점에서 구한 선형 시불변 모델의 오차를 불확실성으로 고려하여 설계한 제어기가 가지기 쉬운 보수성(conservativeness)을 극복하기 위하여, 도립진자 시스템에 대하여 다수의 경사 각도를 선형화의 동작점으로 취하여 복수개의 선형시불변 모델로써 이루어진 하나의 폴리토프 모델(polytopic model)을 구성하였다. 이 모델에 대하여, 볼록 최적화(convex optimization) 알고리즘을 사용하는 LMI 소프트웨어를 사용하여 다목적 성능을 만족하는 제어기를 설계하였다. 폴리토프 모델에 대하여 설계된 제어기로써 제어된 도립 진자는, 비교적 큰 경사 각도의 초기치에 대한 실험에서, 안정하게 연직 위치로 복원되는 제어 효과를 관찰할 수 있었다.

• 한국의상디자인학회지
• /
• 제12권3호
• /
• pp.43-55
• /
• 2010

The major advantages to use CAD System are that it reduce time and effort to manufacture products, and also can demonstrate the condition of the final product prior to the actual manufacturing process of the selected design using the simulation programs in CAD system. Specially in weave design, for use as Computer-Aided Weaving system, the complicated Dobby weave can figured out easily through calculating the complex weave plans of multi shafts. As to one of dobby weave structures, Supplementary warp is the warp threads which are in addition to the regular warps of the woven fabrics, and used for decorating the band or expressing some patterns. The purpose of this study is to research the weave design of Supplementary warp using Computer-Aided Weaving system, which is dobby weave design program of Weave Point. For performing this design study, it was researched the classified woven fabrics depending upon weaving processing, Computer-Aided Weaving system, and the characteristic of Supplementary warp fabrics. On the basis of the theoretical research, Supplementary warp was worked for the 24-shafts AVL computer dobby loom that applied to the various patterned images. The design work was done by Weave Point program of dobby weave, and simulated to fabrics before woven into the computer dobby loom. To see the visual images of fashion items, these simulated bobby fabrics were processed by three-dimension modeling through YoungWoo CNI CAD system. All the patterns of the Supplementary warp in this study could be applied for decorating the fashion clothing and accessories.

• 한국실내디자인학회논문집
• /
• 제31호
• /
• pp.49-55
• /
• 2002

The purpose of this study is to suggest specific function of each areas and way to express reasonable interior elements within interior design of sports center in Korea. The method of this research is case study of sports center In various fields since 1980. During the study, it Is very clear that the most important points in designing of sports centers interior space to accomodate main body training areas and service area for the users. The other point is to explain within the space plan that there should be a clear understanding of general regulation for the installation element, function and behavioral facts. The social, cultural roles of sports center must have the function as a multi service facility. In summary this research is to present datas and suggestion to various areas in sports center and refine its new meaning of sports center space plan with much better designing.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
• /
• pp.1028-1033
• /
• 1991

This paper describes the design of a neural network estimator to estimate weld pool sizes for on-line use of quality monitoring and control in GMA welding processes. The estimator utilizes surface temperatures measured at various points on the top surface of the weldment as its input. The main task of the neural net is to realize the mapping characteristics from the point temperatures to the weld pool sizes through training, A series of bead-on plate welding experiments were performed to assess the performance of the neural estimator.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.1668-1674
• /
• 2011

Door Inside Lamp of railway rolling stock is installed on interior of the side doors and illuminated at door opening and closing, isolation and fault. So drivers or passengers can notice the door status visually. In the past, a single color or Bi-color LED Lamps have been using and one ~ multiple lamp was used to implement the feature according to client's requirements. (Example: Total of between 2 and 4 lamps are required for the Warning / Emergency operation / Isolation / Fault.) However these design is not easy to apply if there is the mounting space restrictions and the problems such as rising costs can be caused. In addition, it has vulnerability from point of view aesthetic aspects. Therefore the lamp type has been required that has small size and number of colors in order to resolve these problems. Recently multi LED type door status indication lamp have been developed that can meet the requirements and this lamp has been applied in many railway projects. In this study, I'll introduce the general characteristics and mechanical & electrical characteristics of multi LED type door status indication lamp to help development of this kinds of lamp.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.1466-1472
• /
• 2011

Door Inside Lamp of railway rolling stock is installed on interior of the side doors and illuminated at door opening and closing, isolation and fault. So drivers or passengers can notice the door status visually. In the past, a single color or Bi-color LED Lamps have been using and one ~ multiple lamp was used to implement the feature according to client's requirements. (Example: Total of between 2 and 4 lamps are required for the Warning / Emergency operation / Isolation / Fault.) However these design is not easy to apply if there is the mounting space restrictions and the problems such as rising costs can be caused. In addition, it has vulnerability from point of view aesthetic aspects. Therefore the lamp type has been required that has small size and number of colors in order to resolve these problems. Recently multi LED type door status indication lamp have been developed that can meet the requirements and this lamp has been applied in many railway projects. In this study, I'll introduce the general characteristics and mechanical & electrical characteristics of multi LED type door status indication lamp to help development of this kinds of lamp.

• 제어로봇시스템학회논문지
• /
• 제18권8호
• /
• pp.780-786
• /
• 2012

Surveillance has become one of promising application areas of wireless sensor networks which allow for pervasive monitoring of concerned environmental phenomena by facilitating context awareness through sensor fusion. Existing systems that depend on a postmortem context analysis of sensor data on a centralized server expose several shortcomings, including a single point of failure, wasteful energy consumption due to unnecessary data transfer as well as deficiency of scalability. As an opposite direction, this paper proposes an energy-efficient distributed context-aware surveillance in which sensor nodes in the wireless sensor network collaborate with neighbors in a distributed manner to analyze and aware surrounding context. We design and implement multi-modal sensor stations for use as sensor nodes in our wireless sensor network implementing our distributed context awareness. This paper presents an initial experimental performance result of our proposed system. Results show that multi-modal sensor performance of our sensor station, a key enabling factor for distributed context awareness, is comparable to each independent sensor setting. They also show that its initial performance of context-awareness is satisfactory for a set of introductory surveillance scenarios in the current interim stage of our ongoing research.