• Journal of Digital Convergence
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• v.12 no.3
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• pp.7-16
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• 2014

This study aims to analyze the key logic of the current C-P-N-D ICT ecological system, to find out the shortcomings of the current system, and then to offer policy suggestions for the establishment of a new creative contents industry ecological system; that is, ICCT (Information, Communication, Contents and Technology) System.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.706-713
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• 1994

Isothermal vapor-Liquid equilibrium data have been measured for binary systems MTBE-methanol, MTBE-n-heptane, and methanol-n-heptane at $45^{\circ}C$ and $65^{\circ}C$ by using head space gas chromato-graphy (H.S.G.C). Among these systems a minimum azeotrope was observed in both of MTBE-methanol system and n-heptane-methanol system. Particularly n-heptane-methanol system has a heterogeneous minimum azotrope since it has an immisible region. These equilibrium data were correlated with the excess Gibbs energy model, and the thermodynamic consistency test was also carried out by using Redlich-Kister equation.

• Korean Journal of Veterinary Service
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• v.30 no.2
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• pp.259-267
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• 2007

A study on the relation between some husbandry practices and brucellosis in goats in Bangladesh was conducted at selected areas of Mymensingh and Dhaka district, Bangladesh, from March 2005 to May 2006. Sera from 300 goats were tested by Rose bengal test (RBT), plate agglutination test (PAT), tube agglutination test (TAT) and mercaptoethanol test (MET). Out of the 300 goats, 1.670% (n=5) were positive to RBT and PAT respectively, and 2.0% (n=6) were positive to TAT and 2.33% (n=7) were positive to MET. The prevalence of brucellosis was bigger in goats reared collectively (n=2, 4%) than reared individually (n=5, 2%), and bigger in goats housed with concrete floor (n=2, 4%) than that of bare floor (n=5, 2%). The rate of brucellosis was higher in goats keep separately (n=6, 2.61%) than that of kept with other animals (n=1, 1.43%) especially with cattle. Out of 290 goats from free grazing, 7 were positive but no positive reactor(n=10) was found in non grazing goats. In conclusion, however, seroprevalence of brucellosis had no statistically significant association with rearing type, housing type and grazing or not.

• Journal of Animal Environmental Science
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• v.12 no.1
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• pp.21-28
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• 2006

This study was carried out to measure and analyze the characteristics of noise and vibration, and to analyze their effects on the productivity of layers, mechanical troubles, and abnormal wear-out failure of facilities and equipment of the layer house. The measurements of noise and vibration were taken at 13 layer farms nationwide for the operations of feed supplier system, feed distribution system, automatic egg collection system, ventilation system, blot conveyer for layer feces, and fur the case of with and without their operation by a sound level meter and a vibration measuring system in the layer house equipped with upright multi-tier cages. Measurement results showed that normal times were noise(N) 82 dB and vibration(V) 0.2072 cm/s, feed supplier system were 90 dB(N) and 2.8560 cm/s(V), feed distribution system were 90 dB(N) and 2.0222 cm/s(V), automatic egg collection system were 87 dB(N) and 0.1865 cm/s(V), ventilation system 88 dB(N) and 2.5364 cm/s(V), belt conveyer fur layer feces were 88 dB(N) and 0.2387 cm/s(V), and then maximum values of noise and vibration were 90 dB and 2.8560 cm/s, respectively, when feeding systems(feed supplying system and feed distribution system) were operated. Based on these results, an experiment is being conducted to find out the effect of noise and vibration on the productivity of layers in the layer house equipped with upright multi-tier cages.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.4
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• pp.290-297
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• 2013

The increasing level of operation in high-tech industry is likely to require ever more complex structure in reliability problem. Furthermore, system failures are more significant on society as a whole than ever before. Reliability redundancy optimization problem (RROP) plays a important role in the designing and analyzing the complex system. RROP involves selection of components with multiple choices and redundancy levels for maximizing system reliability with constraints such as cost, weight, etc. Meanwhile, previous works on RROP dealt with system with perfect failure detection, which gave at most a good solution. However, we studied RROP with imperfect failure detection and switching. Using absorbing Markov Chain, we present not a good solution but the optimal one. In this study, the optimal system configuration is designed with warm and cold-standby redundancy for k-out-of-n system in terms of MTTF that is one of the performance measures of reliability.

• Journal of Korean Vacuum Science & Technology
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• v.2 no.1
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• pp.25-31
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• 1998

The reliability of fluorine doped silicon oxide (SiOF) films for intermetal dielectrics in multilevel interconnections of ultra-large scale integrated circuits (ULSIs) is investigated. SiOF films were deposited by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECRPECVD) using H-free source gases, i.e., SiF4 and O2. The effect of post plasma treatment on the moisture absorption and dielectric properties of SiOF films was carried out I terms of air exposure time, The reliability test of Cu/TiN/SiOF/Fi specimen was carried out in terms of temperature by rapid thermal annealing (RTA) in N2 ambient. After O2 plasma treatment,, no appreciable peak directly related to moisture absorption was detected. The capacitance-voltage (C-V) characteristics of the O2 plasma treated SiOF film showed that the film remained to hold the sound dielectric properties even after boiling treatment. The Cu/TiN/SiOF/Si system was found to be reliable up to $600^{\circ}C$.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.567-570
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• 1988

This paper describes the design of FIR filtering DSP-chip that can be operated without programming. The proposed DSP-chip has not only the improvement of execution time but also selectivity of filter length from N=1 to N=128. Hilbert Transformer can be designed from this chip. FIR filter system is composed of Data memory/Control Unit, external memory and multiplier-accumulator. Data memory/Control Unit is laid out in this paper.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.11-20
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• 2024

In the recent era of NewSpace, unlike high-reliability satellites of the past, low-reliability satellites are being developed and mass-produced at a lower cost to launch constellations satellites. To achieve cost-effective cluster satellite development, satellite users and developers need to assess the feasibility of maintaining mission performance over the expected lifespan when cluster satellites are launched. Plans for replacements due to random failures should also be established to maintain performance. This study proposed a method for assessing system reliability and availability to maintain mission performance and establish replacement strategies for Earth observation constellation satellites. In this study, a constellation reliability and availability model considering mission performance required for a satellite constellation, situations of satellite backup, and additional ground backups was established. The reliability model was structured based on the concept of a k-out-of-n system and the availability model used a Markov chain model. Based on the proposed reliability model, the minimum number of satellites required to meet mission requirements was defined and satellites needed in orbit during the required mission period to satisfy mission reliability were calculated. This research also analyzed the number of spare satellites in orbit and on the ground required to meet the desired availability during required service period through availability analysis.

• Journal of Biosystems Engineering
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• v.16 no.4
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• pp.355-362
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• 1991

The objective of this study was to develop an electronic-hydraulic depth control system. Simulation was carried out to investigate the responses of the control system, and indoor experiments were carried out to confirm the simulation results of the control system. Field experiments were carried out to compare the newly-developed electronic-hydraulic depth-control system with the existing mechanical-hydraulic position control system in terms of the performance of depth control. The electronic-hydraulic depth control system showed better performance than the existing mechanical-hydraulic hitch control system for the forward speeds of tractor less than 7 km/h. It is concluded that the new control system could be adapted to the existing tractors with slight modifications to the conventional mechanical-hydraulic hitch control systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1948-1954
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• 2014

Advances in IT technology and modernization of AtoN(Aids to Navigation) facility has increased the unmanned operation of AtoN. However, in AtoN facilities, accessibility is low and it is not able to perform maintenance on the bad weather at the time. In connection with this, in this paper, by applying the protocol of the enhanced dual LED marine lantern, we implemented the short-range monitoring system for a mobile terminal. System implemented in this paper can be carried out confirm the operation status, inspection or control of the dual LED marine lantern at a short distance. Also, it is possible to reduce maintenance costs and prevent accidents during inspection of AtoN. At the same time, it enables the operation test easily without disassembling the product, effective AtoN operation is possible. We tested the system that has been implemented using prototype of the LED marine lantern and confirmed state informations and controlled the behavior of the system in real time.