• International Journal of Control, Automation, and Systems
• /
• 제6권5호
• /
• pp.670-676
• /
• 2008

While the matrix converter has many advantages that include bi-directional power flow, a size reduction, a long lifetime, and sinusoidal input currents, it is vulnerable to the input voltage disturbances, because it directly exchanges the input voltage to the output voltage. So, in this paper, a critical evaluation of the effect of various abnormal voltage conditions like unbalanced power supply, balanced non-sinusoidal power supply, input voltage sags and short time blackout of power supply on matrix converter fed induction motor drives is presented. The operation under various abnormal conditions has been analyzed. For this, a 230V, 250VA three phase to three phase matrix converter (MC) fed induction motor drive prototype is implemented using DSP based controller and tests have been carried out to evaluate and improve the stability of system under typical abnormal conditions. Digital storage oscilloscope & power quality analyzer are used for experimental observations.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
• /
• pp.47-50
• /
• 2004

In this paper, we implement an Elliptic Curve Cryptosystem(ECC) processor for DTCP. Because DTCP(Digital Transmission Content Protection) uses GF(p), where p is a 160-bit prime integer, we design a scalar multiplier based on GF(p). The scalar multiplier consists of a modular multiplier and an adder. The multiplier uses montgomery algorithm which is implemented with CSA(Carry-save Adder) and CLA(Carry-lookahead Adder). Our new scalar multiplier has been synthesized using Samsung 0.18 um CMOS technology and the maximum operation frequency is estimated 98 MHz, with the size about 65,000 gates. The resulting performance is 29.6 kbps, that is, it takes 5.4 msec to process a 160-bit data frame. We assure that this performance is enough to be used for digital signature, encryption/decryption, and key exchanges in real time environments.

• The Korean Journal of Ecology
• /
• 제19권1호
• /
• pp.9-19
• /
• 1996

The model PINUSCO2 hased of physiology was creted to simulate carbon dioxide budget in a population of red pine(pinus densiflora) which is one of the dominant species in Korea. Driving forces of PINUSCO2 are global radiation, maximum and minimum air temperatures. State variables fo the model are standing crops of leaf, branch, trunk and root of the red pine population. PINUSCO2 calculates net photosynthesis of canopy and respiration of each organ with 1 hour time step. PINUSCO2 estimated the annual gross productivity, respiration and net productivity of the red pine population as 43.99, 24.55, and 19.44 ton CO2·ha-1·yr-1, respectively, at the study sity(35°58′00"N, 128°25′35"E). PINUSCO2 showed that the red pine population grew mainly in spring and fall, and that in summer daily net population productivity frequently became negative.

• Journal of Advanced Marine Engineering and Technology
• /
• 제34권1호
• /
• pp.125-132
• /
• 2010

IEC61162-3 known as NMEA2000 protocol is approved as a standard network of SOLAS ship by ISO and used for the instrument network which exchanges data in real-time. For easy the development of ship network equipments, this study is focused on the development of SoC which can convert to NMEA2000 protocol from various kind of protocols such as TCP/IP, NMEA0183, RS422 and others using FPGA and u-Blaze. In this paper, we composed NMEA2000 protocol stack on FPGA and verified NMEA2000 network communication of FPGA system by connecting with commercialized devices through PC Hyper-terminal and network monitoring program.

• Journal of Advanced Marine Engineering and Technology
• /
• 제25권5호
• /
• pp.1037-1049
• /
• 2001

Considerable interest has evolved in the flow of non-Newtonian fluids in channels of noncircular cross section in compact heat exchanges. Analytical solution was developed for prediction of the flow rate and maximum velocity in steady laminar flow of any incompressible, time-independent non-Newtonian fluids in straight closed and open channels of arbitrary, but axially unchanging cross section. The geometric parameters and function of shear describing the behavior of the fluid model were evaluated for fluid flow among a bundle of rods arranged in triangular and square array. Numerical values of dimensionless maximum velocities, mean velocities, pressure-drop-flow parameters and friction factors were evaluated as a function of porosity and pitch-to-radius ratio.

• 복식
• /
• 제40권
• /
• pp.67-80
• /
• 1998

Being located in the east of the Mediterranean Sea, Cyprus used to play a bridge role of cultural exchanges between the East and the West during period of being occupied. As a consequence the fact that the style of costume might be changed at certain levels during the time is broadly accepted. Basic structure of Cypriot men's clothes during the late of the 19th century to the middle of 20th century is composed of\circled1 baggy trousers(vraka) \circled2 shirt(chemise) \circled3 jacket(ziboune/zibouna) \circled4 waistcoat(yilekko) \circled5 headdress(fez, kourouklin) \circled6 accessories. General composition of women's wear is \circled1 pantaloons(vrandzin) \circled2 shift(poukamiso) \circled3 outer garment(sayia, foustani, Amalia, costume) \circled4 waist kerchief(mandili tis koxas)\circled5 boots(podines)/pumps(goves) \circled6 scarves and accessories. As reviewed above, although men's clothes are still worn on a day to day basis, women's wear continues to exist only for festivals or as a tourist attraction. It was understood that this was an accepted consequence of 20th century modernization and reformation.

• 기술사
• /
• 제43권6호
• /
• pp.27-30
• /
• 2010

Gyeongbu high-speed railway project which comprises the construction of the new line with 417.5km between Seoul and Busan is one of the biggest national projects with approx. 20-trillion-won project cost. The construction was started in June 1992 and afterward phase I (between Seoul and Daegu) was opened in April 2004 and phase II (between Daegu and Busan, 169.5km) is scheduled for opening in the end of October 2010. It is assured that the opening of the entire sections of Gyeongbu high-speed railway will significantly increase productivity and efficiency by improving the land utilization with the promotion of personal and material exchanges induced by the reduction of travel time between regions. Especially, Gyeongbu high-speed railway will be the opportunity to boost speed-up of Korea railway.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
• /
• pp.95-97
• /
• 2005

This paper deals with the implementation of walking for a humanoid robot by ZMP measurement using wireless sensor network. ZMP is measured by FSR sensors which are mounted at each corner of a sole. The wireless sensor network collects the sensor data according and exchanges robot information between host PC and a robot system. The master controller mounted on robot body receives trajectory data from the host PC via sensor network and drives the joint motor based on trajectory data. The time scheduler of the master controller controls the events at the ratio of 100ms. With this configuration, the walking of the humanoid robot KHR-1 could be realized successfully.

• 한국CDE학회논문집
• /
• 제5권1호
• /
• pp.79-87
• /
• 2000

This paper presents an integrated but open product development environment for distributed and collaborative design. The web-based framework, called DOME, allows designers to build integrated models using both local and distributed resources, and to collaborate by exchanging services in a network-centric product development environment. Thus, an integrated model can be created while each participant focuses on his or her own area of expertise. A design problem model is created by connecting modules, which represent specific system components, analysis capabilities/software, disciplines, or organizations relevant to the problem. The modules interact with each other using service exchanges based upon the CORBA standard communication protocol. The goal of this framework is tall provide the ability to rapidly construct integrated design problem models to facilitate collaborative design work, improve product quality and reduce development time. Ultimately, it should allow specialized engineering applications and design problem models to operate under a common design environment.

• 설비공학논문집
• /
• 제27권5호
• /
• pp.241-246
• /
• 2015

Cellular foamed insulation such as polyurethane foam ages and degrades the thermal conductivity. Aging of foam is a result from the diffusion of gases, initially consisting of $CO_2$ but eventually replaced by air from the environment. The variation of the cell gas content with time is primarily influenced by the increase of thermal conductivity of the cellular foam. The weight of foam also changes as the gas diffuses and exchanges. In this study, a weight measurement method has been proposed to evaluate the effective diffusion coefficients of $CO_2$ and Air, $D_{CO2}=7.08504E-11$ and $D_{air}=4.86086E-12$, respectively and are compared with the gas analysis method.