• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.10
• /
• pp.3789-3793
• /
• 2010

To investigate accuracy of graduated scale of schematic retinoscope training eye(schematic eye) and induced effect when measured at off-axis from visual axis. Two skilled retinoscopist measured refractive power using retinoscope in random order. Seven schematic eyes from a single manufacturer were recruited and set to mark +4.00 to -6 diopter(+4, +3, +2, +1, 0, -1, -2, -3, -4, -5, -6). After introducing +2.00 diopter trial lens(50cm working lens), neutral distance was measured at 180 degree to estimate accuracy of scale, and refractive power measured at 0, 5, 10, 15 and 20 degree off-axis to see if any error was induced. According to the results measured by two specialists, in six of seven schematic eye, scale setting varied (p<0.05) and measured refractive power at 5, 10, 15 and 20 degree off-axis from visual axis were $-0.13{\pm}0.06$, $-0.29{\pm}0.06$, $-0.58{\pm}0.11$, and $-0.83{\pm}0.16$ diopter respectively. In some schematic eye, scale graduated on the schematic eye and scale measured by retinoscopy could be different and if retinoscopy is performed off-axis from visual axis, any measuring error can be caused.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.12 no.4_1
• /
• pp.129-136
• /
• 1992

A precedure for recovering surface displacement from a time series of pressure measured by a pressure gage in a shallow water (that is, FFTM, LCM. IWM) is investigated with respect to a proper cut-off-frequency of a frequency response function for the accurate recovery of wave height and period. The authors examined the applicability of above mentioned three transformation procedures through field observations and laboratory experiments and the following results are obtained. i) The cut-off-frequency of the frequency response function used in FFTM is deeply depend on both the frequency response of the pressure sensor and the water depth at the sensor. In this study, a relatively accurate surface displacement can be recovered when the frequency response function is cut off at the frequency corresponding to kh=3.0 where k is a wave number at the depth of h. The frequency response function in the region higher than the cut-off-frequency is set constant to be the value at the cut-off-frequency. ii) The transformed surface displacements by LCM are affected by the small waves of short periods included in the measured pressure. It is found that pressure variation whose local frequency is higher than kh=1.5 has to be neglected to recover surface displacement sufficiently. iii) In IWM, the linear pressure response function is usually utilized by multiplying a coefficient N which is a function of the frequency (or kh) and takes a value around unity. However, in this study, a constant value of N(=1.0) gives a relatively accurate recovery of surface displacements.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.465-467
• /
• 2015

This paper implements a dual-mode power strip controller (PSCtrl) with environmental sensors which cooperates with Android-based smartphones. According to the statistics on fires in housing facilities, unidentified electrical fires account for 23.4%. In order to reduce these fire accidents caused by user carelessness and protect life and property, smart power control techniques with improved user convenience are required. For this reason, the implemented dual-mode PSCtrl controls ON-OFF operations of a power strip in two ways (e.g. manual and automatic modes) by cooperating with Android-based smartphones provided with environmental data from light, temperature, and humidity sensors. In manual mode, users check environmental data displayed on Android-based smartphones, forcibly controlling the ON-OFF operations through the dual-mode PSCtrl, and in automatic mode, when environmental data exceeds the threshold set by users in advance, the dual-mode PSCtrl automatically controls the ON-OFF operations. Some experimental tests verify successful dual-mode operations of the implemented dual-mode PSCtrl.

• Journal of information and communication convergence engineering
• /
• v.5 no.2
• /
• pp.140-143
• /
• 2007

Fingerprint Recognition System is made up of Off-line treatment and On-line treatment; the one is registering all the information of there trieving features which are retrieved in the digitalized fingerprint getting out of the analog fingerprint through the fingerprint acquisition device and the other is the treatment making the decision whether the users are approved to be accessed to the system or not with matching them with the fingerprint features which are retrieved and database from the input fingerprint when the users are approaching the system to use. In matching between On-line and Off-line treatment, the most important thing is which features we are going to use as the standard. Therefore, we have been using "Delta" and "Core" as this standard until now, but there might have been some deficits not to exist in every person when we set them up as the standards. In order to handle the users who do not have those features, we are still using the matching method which enables us to make up of the spanning tree or the triangulation with the relations of the spanned feature. However, there are some overheads of the time on these methods and it is not sure whether they make the correct matching or not. In this paper, introduces a new data structure, called Union and Division, representing binary fingerprint image. Minutiae detecting procedure using Union and Division takes, on the average, 32% of the consuming time taken by a minutiae detecting procedure without using Union and Division.

• Korean System Dynamics Review
• /
• v.12 no.2
• /
• pp.127-151
• /
• 2011

The purpose of this study is to examine measures to improve government's supply oriented housing policy in population declining cities. For this purpose, system dynamics simulation method was used to build urban-housing model and different sets of housing policies were tested to see their impact on local housing problems. Simulation result shows that there is no best set of housing policies that can solve all housing problems in population declining cities. It also indicates that housing policy that solve one type of problems can worsen other type of problems. Housing policy that increases population size has negative effect of housing oversupply. It also increases proportion of old houses in population declining cities. However, housing policy that makes city younger with newer houses tends to increase housing shortage and housing price. So, policy choice needs to be made with clear understanding of trade off between different policies. The result also shows it is difficult to expect a full scale effect of housing policy on local housing problems unless it is executed with regional economic development policy because local housing problems are so closely related with local economic problem in population declining local cities.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.11 no.1
• /
• pp.26-35
• /
• 1987

As an attempt to make the multi-objection for the line design of the rope way, the resulted formulas from the catenary curve as exact ones were summarized, and it was found out that the Kuhn-Tucker's optimality conditions and regions of the objective functions can analytically be expressed with dimensionless parameters. The Pareto's optimum solution set was analytically obtained through the objective function-the minimum relation of $W^{*}$, and $W^{*}$ is a trade-off relation. From this, The dimension of a rope and the value of an initial tension that are the standard in design of the rope way were determined. It was concluded that $V^{*}$ should become minimum, and that the ratio of the dimension of rope to the value of and initial tension become larger than superposition factor corresponding to curve AB.to curve AB.

• Ocean Science Journal
• /
• v.42 no.4
• /
• pp.231-240
• /
• 2007

Three marine fish species are recorded for the first time from Korean waters: a molid (Ranzania laevis, 1 specimen, 279.8 mm SL) and bramid (Pterycombus petersii, 3 specimens, 95.3-214.0 mm SL) collected from a large purse seine off Jeju Island, in the southern sea of Korea, and a carangid (Carangoides dinema, 1 specimen, 194.5 mm SL) from a set net in coastal waters off Busan, in the southeastern sea of korea. R. laevis is characterized by a wedge-shaped body and truncated clavus; P. petersii by the dorsal fin origin above or behind the posterior margin of eye, and dorsal and anal fins depressible; and C. dinema by a row of black blotches along the second dorsal fin base, the curved part of the lateral line longer than straight part, and 18 and 16 dorsal and anal fin rays, respectively. New Korean names are proposed for all three species.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.7B
• /
• pp.1268-1278
• /
• 1999

In this paper, we propose an analytic method for dimensioning of traffic descriptors at the leaky bucket-based UPC for VBR MPEG video traffic on ATM networks. We analytically derive cell violation probabilities at the UPC by using the proposed scene-based video traffic model, and then we show that it is possible to select sets of traffic descriptors that have the same required violation probability. For two example video traces, numerical results show that our proposed traffic descriptors dimensioning method can approximate well the simulation-based traffic control results of the real video traces. When the effective bandwidth allocation method of an ON/OFF model is used for the call admission control in the networks, we present an efficient traffic descriptor selection method by studying the allocated bandwidth to each possible traffic descriptor set.

• Progress in Superconductivity
• /
• v.5 no.1
• /
• pp.13-16
• /
• 2003

In this work, we have studied about an RSFQ (Rapid Single Flux Quantum) switch element. The circuit was designed, simulated, and laid out for mask fabrication. The switch cell was composed of a D flip-flop, a splitter, a confluence buffer, and a switch core. The switch core determined if the input data could pass to the output. “On” and o“off” controls in the switch core could be possible by utilizing an RS flip-flop. When a control pulse was input to the “on” port, the RS flip-flop was in the set state and passed the input pulses to the output port. When a pulse was input to the “off” port, the RS flip-flop was in the reset state and prevented the input pulses from transferring to the output port. We simulated and optimized the switch element circuit by using Xic, WRspice, and Julia. The minimum circuit margins in simulations were more than $\pm$20%. We also performed the mask layout of the circuit by using Xic and Lmeter.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
• /
• v.8 no.1
• /
• pp.12-17
• /
• 2009

In this paper, We play it for the purpose of study about the power amplifier which applied DGS and adaptive bias circuit structure to general Doherty amplifier for the efficiency of a RF power amplifier and a linearity improvement in the WiBro band. As for the IMD3, 3.4dBc was improved with -26.3dBc when we did the measurement result existing Doherty power amplifier and comparison of the Doherty power amplifier which applied an adaptive bias circuit and the DGS which proposed in this paper, and the mean power efficiency verified what was increased in 37%. Also, we were able to know PAE of 36.6% with output power 34.0dBm in P1dB when magnitude of an input signal was 25.6dBm. we did 6dB back off in output P1dB in order to confirm the ACPR which was a nonlinear characteristic and measured the ACPR. we showed the -34.55dBc which was a value of -34.5dBc or below in the 4.77MHz off-set that was a transmission standard. Therefore, we were able to know that we were satisfied with a spectrum mask standard.