• Korean Chemical Engineering Research
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• 제43권3호
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• pp.371-379
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• 2005

Adsorption equilibria of the gases $H_2$, $CH_4$, and $C_2H_4$ and their binary mixtures on activated carbon (Calgon co.) have been measured by static volumetric method in the pressure range of 0 to 18 atm at temperatures of 293.15, 303.15, and 313.15 K. From the parameters obtained from single component adsorption isotherm, multi-component adsorption equilibria could be predicted and compared with experimental data. The binary experimental data were applied to four models : extended Langmuir, extended Langmuir-Freundlich, Ideal Adsorbed Solution theory (IAST), and Vacancy Solution Model (VSM). The models were found to describe the experimental data with a reasonable accuracy. Extended L-F model predicts equilibria of mixture better than any other model.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제27권10C호
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• pp.887-901
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• 2002

Software management model divided into the software project model and design estimation model, software matrices model, reliability growth model, process improvement model(or process maturity model) etc. Among these software management models, software complexity model make an estimated of the product software. For a practice of software managed, need to guideline of the static analysis of software. Especially, Software complexity model introduced for the estimation of software quantity and program complexity. In case of measurement the software matrices, its need for us to analysis of software quality and products. On the other hand, we known that complexity program include many defects and consuming of source cost. So, we apply to complexity model using of the program complexity, control structure and volume matrices, interface metrics, process complexity metrics method. In this paper, we represent that the analysis of fault data detected during the system test. Also, we analysis of program control structure and interface, volume matrices in various aspect of switching software. Others, their results utilized similar of project and system development.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제35권1C호
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• pp.24-32
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• 2010

In this paper we proposed an object tracking system that detects the abandoned and removed objects, which is to be used in the intelligent surveillance applications. After the GMM based background subtraction and by using histogram method, the static region is identified to detect abandoned and removed objects. Since the system is implemented on DSP chip, it operates in realtime and is programmable. The input videos used in the experiment contain various indoor and outdoor scenes, and they are categorized into three different complexities; low, midium and high. By 10 times of experiment, we obtained high detection ratio at low and medium complexity sequences. On the high complexity video, successful detection ratio was relatively low because the scene contains crowdedness and repeated occlusion. In the future work, these complicated situation should be solved.

• Korean Journal of Environmental Agriculture
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• 제6권2호
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• pp.66-72
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• 1987

Sensitivity of the three freshwater fish, Cyprinus carpio, Oryzias latipes (wildtype indigenous to Korea), and O. latipes (Japanese killifish) to 30 pesticide formulations were studied in terms of 48 hr $LC_{50}$ determined with the static method. The correlation between C. carpio and O. latipes (Japanese killifish) was higher than that between C. carpio and O. latipes with correlation coefficients of 0.89 and 0.80, respectively. The sensitivity of O. latipes and O. latipes (Japanese killifish) to pesticides showed very high correlation with a coefficient of 0.93. Therefore, it is suggested that the acute toxicity data concerning O. latipes (Japanese killifish) could represent those C. carpio or O. latipes which are indigenous species in Korea. Also, it is found that the present protocol for the toxicity test with carp in Korea has difficulties in maintaining the proper concentration of dissolved oxygen in the test chamber because of the abrupt decrease of dissolved oxygen to 2mg/l, which is not acceptable according to general guidelines of foreign countries.

• Computers and Concrete
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• 제20권4호
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• pp.491-502
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• 2017

In this research, the application of ultrasonic pulse velocity (UPV) test as a nondestructive method for estimating some of the mechanical and dynamic properties of reactive powder concrete (RPC) containing steel and polyvinyl alcohol (PVA) fibers, as well as their combination was explored. In doing so, ten different mix designs were prepared in 19 experimental groups of specimens containing three different volume contents of steel fibers (i.e., 1, 2, and 3 %) and PVA fibers (i.e., 0.25, 0.5, and 0.75 %), as well as hybrid fibers (i.e., 0.25-0.75, 0.5-0.5, and 0.75-0.25 %). The specimens in these groups were prepared under the two curing regimes of normal and heat treatment. Moreover, the UPV test results were employed to estimate the compressive strength, dynamic modulus, shear modulus, and Poisson's ratio of the RPC concrete and to investigate the quality level of the used concrete. At the end, the effect of the specimen shape and in fact the measuring distance length on the UPV results was explored. The results of this research suggest that the steel fiber-containing RPC specimens demonstrate the highest level of ultrasonic pulse velocity as well as the highest values of the mechanical and dynamic properties. Moreover, heat treatment has a positive effect on the density, UPV, dynamic modulus, Poisson's ratio, and compressive strength of the RPC specimens, whereas it leads to a negligible increase or decrease in the shear modulus and static modulus of elasticity. Furthermore, the specimen shape affects the UPV of fiber-lacking specimens while negligibly affecting that of fiber-reinforced specimens.

• Steel and Composite Structures
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• 제25권1호
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• pp.79-92
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• 2017

Initial damage to a stud due to corrosion, fatigue, unexpected overloading, a weld defect or other factors could degrade the shear capacity of the stud. Based on typical push-out tests, a FEM model and theoretical formulations were proposed in this study. Six specimens with the same geometric dimensions were tested to investigate the effect of the damage degree and location on the static behavior and shear capacity of stud shear connectors. The test results indicated that a reduction of up to 36.6% and 62.9% of the section area of the shank could result in a dropping rate of 7.9% and 57.2%, respectively, compared to the standard specimen shear capacity. Numerical analysis was performed to simulate the push-out test and validated against test results. A parametrical study was performed to further investigate the damage degree and location on the shear capacity of studs based on the proposed numerical model. It was demonstrated that the shear capacity was not sensitive to the damage degree when the damage section was located at 0.5d, where d is the shank diameter, from the stud root, even if the stud had a significant reduction in area. Finally, a theoretical formula with a reduction factor K was proposed to consider the reduction of the shear capacity due to the presence of initial damage. Calculating K was accomplished in two ways: a linear relationship and a square relationship with the damage degree corresponding to the shear capacity dominated by the section area and the nominal diameter of the damaged stud. This coefficient was applied using Eurocode 4, AASHTO LRFD (2014) and GB50017-2003 (2003) and compared with the test results found in the literature. It was found that the proposed method produced good predictions of the shear capacity of stud shear connectors with initial damage.

• The Journal of Korean Academy of Prosthodontics
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• 제31권3호
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• pp.303-316
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• 1993

The purpose of this study was to analysis the stress distribution induced by three unit PFM bridges and various cantilever bridges replacing maxillary latersal incisor. The simplified two-dimensional photoelastic models used for this study was contructed in the folio- wing way. CR/R ratio was designed to be 1 : 1, 1 : 1.25 and 1 : 1.5. The pontics of cantilever bridge supported by maxillary canines consisted of wrap-around type, rest-extension type, and simple type. 3-unit PFM bridge was constructed with traditional method. 1kg vertical static load was applied on the center of the incisal edge of the pontic. The stress pattern was examined and recorded by photography. The results obtained were as follows ; 1. The magnitude of stress on the abutment root apex area of a traditional 3-unit bridge was the lowest. 2. The model of cantilevered pontic with a rest showed the relatively well distributed stress around the abutment tooth. The model with simple pontic generated the greatest stress concentration in the supporting structure of the abutment tooth. 3. As the height of bone level reduced, the rotational and vertical force increased around the abutment tooth. 4. The stress concentration of the 3-unit bridges occured on the root apex and stress concentration of the cantilever briage occured on the root apex and cervix area, 5. In the case of the cantilever bridge, stress concentrated distally on the root apex area of the abutment tooth and additional stress was observed mesially on the upper part of the root. Especially in the case of the simple pontic, was phenomenon was more apparent than the others. 6. Force applied to cantilevered pontic was transmitted to the adjacent central incisor through the contact surface. Stress was markedly observed on the mesial cervix area in the case of simple pontic and on the root apex area in the case of wrap-around type and rest-extension type.

• The Transactions of the Korean Institute of Power Electronics
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• 제10권6호
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• pp.626-633
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• 2005

This paper proposes a new 2MVA SSFG(Sag Swell Flicker Generator) injecting voltage by using series inverter. The proposed SSFG composes series inverter, DC capacitor as energy storage, rectifier and voltage clamp circuit. This SSFG is designed to generate typical power disturbances, such as voltage sag/swell, over/under voltage and voltage flicker. Also it is designed to generate unexpected voltage phase jumping waveform by controlling the series inverter. In this paper, three kinds of control methods for the proposed 2MVA SSFG we investigated by PSIM simulation. Also typical voltage sag, swell, flicker waveforms are implemented by adopting effective control method.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제38A권9호
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• pp.810-816
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• 2013

In this paper, we propose a SSD (simultaneous single-band duplex) system using Digital Cancellation. Also, we propose a method for Digital Cancellation when RF Cancellation is effectively performed. The proposed system has estimation frame for effective self-interference channel estimation in time-domain. The proposed system calculates signal power for selection of optimal coefficient after digital cancellation. Then, the proposed system selects coefficient of minimum signal power. Further, the proposed system uses LDPC code to minimize the effects of remaining self-interference signal. The proposed system shows BER performance of at 20dB by cancelling self-interference and iterating LDPC code. That is, the proposed system shows that the SSD communication is possible in static self-interference channel.

• The Transactions of the Korea Information Processing Society
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• 제6권9호
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• pp.2479-2492
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• 1999

Network management system(NMS) provides not only effective monitoring and controlling of network which consists of heterogeneous network elements but prompt response to users' need for high-level communication services. Recommendations of ITU-T and ISO stipulate the managerial abstraction of static and dynamic characteristics of network elements, management functions as well as management communication protocol. But the current description method does not provide the formal mechanism for the behavior characteristics of managed objects in clear manner but in natural language form, the complete specification of managed objects is not fully described. In this paper, we describe determinants for the behaviour of managed objects applicable to every managed object, and present a language for specifying behavioral aspects of managed objects based on their temporal and active properties.