• Journal of Animal Environmental Science
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• v.10 no.2
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• pp.111-118
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• 2004

This study analyzed temperature increase, microorganism changes, and inactivation of pathogenic microorganisms in pig slurry when treated with thermophilic microorganisms in Thermophilic Aerobic Oxidation(TAO) system. An amount of $6 m^3$ of pig slurry was treated in an $18 m^3(3.0\times2.5\times2.4 m)$ reactor for 5 to 7 days in two groups: the control of pig slurry only and the treatment of pig slurry with 6 liters of thermophilic microorganism(Bacillus sp.). To study the microorganism changes in the reactor, the populations of aerobic mesophilic microorganisms, thermophilic microorganisms and general pathogens were analyzed. To study the inactivation of pathogenic microorganisms, the levels of E. coli, Salmonella sp, Crytosporidium parvum and Giardia lamblia were analyzed. The temperature inside the reactor ranged from 18 to $62^{\circ}C$ for the control while far the treatment group it ranged from 18 to $66^{\circ}C$, showing a slightly higher array. With regard to changes in microorganisms, both mesophilic and thermophilic organisms decreased from $3.1\times10^6$ to $1.2\times10^2$ CFU/ml and from $1.0\times10^4$ to $8.0\times10^1$ CFU/ml, respectively, in the control. In the treatment, on the other hand, mesophilic organisms decreased from $3.0\times10^8$ CFU/ml to $8.6\times10^5$ CFU/ml while thermophilic organisms increased sharply from $2.0\times10^6$ to $1.2\times10^8$ CFU/ml. For pathogens, Salmonella and Giardia were not detected either before or after the treatment, while E. coli and C. parvum were found to be $10^5$ CFU/ml each before treatment and negative after it. From this experiment, it was concluded that thermophilic microorganisms could effectively sanitize liquid compost by generating high temperature in the TAO system, which in turn would inhibit the growth of pathogenic organisms.

• Journal of applied mathematics & informatics
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• v.36 no.5_6
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• pp.491-504
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• 2018

In this article, we consider a fourth order nonlinear difference system. By making use of the critical point theory, we obtain some new existence theorems of at least one periodic solution with minimal period. Our main approach used in this article is the variational technique and the Saddle Point Theorem.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.4
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• pp.19-26
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• 2002

This is a brief report on the development of a system which provides fishing vessels with a real-time key information that can direct to regions of high fish density. Water temperature and Plankton distribution are the base parameters and various public information have been examined and summarized. The suface water temperature can be obtained from NOAA's high resolution infrared data base and the vertical water temperature can be obtained from TAO/TRITON's buoy near the equator and ARGOS's drifting buoy covering wider Pacific ocean. MODIS's data is also utilized for sea color information. A model data format is proposed and a few examples are demonstrated.

• Journal of Animal Environmental Science
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• v.19 no.2
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• pp.81-88
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• 2013

We planned to study how the chemical disposal designed by SOP can affect on physicochemical compositions of the livestock excrement. According to Livestock Manure Management Scheme, we experimented in two steps; the first step, NaOH treatment-Citric acid neutralization, and then the second procedure, Thermophilic Aerobic Oxidation (TAO) system. Physicochemical compositions of the 3-days-old samples after NaOH treatment were pH 10.31, EC 24.54 mS/cm, SCOD 3,022 mg/L, T-N 4,315 mg/L, $NH{_4}^+-N$ 1,960 mg/L, and not detected E. coli.. And those of one-day-old samples after citric acid neutralization were pH 7.36, EC 32.89 mS/cm, $SCOD_{Mn}$ 12,733 mg/L, T-N 4,787 mg/L, $NH{_4}^+-N$ 2,450 mg/L, and E. coli. not detected. In contrast, the physicochemical compositions of the treatment plots after the second treatment with TAO system (72hr) were pH 9.42 EC 24.21 mS/cm, $SCOD_{Mn}$ 3,660 mg/L, T-N 3,616 mg/L, $NH{_4}^+-N$ 1,190 mg/L, and no detection of E. coli.

• Computers and Concrete
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• v.12 no.6
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• pp.775-783
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• 2013

A novel reliability-based work model of k/n (G) system has been developed. Unit failure probability is given based on the load and strength distributions and according to the stress-strength interference theory. Then a dynamic reliability prediction model of repairable k/n (G) system is established using probabilistic differential equations. The resulting differential equations are solved and the value of k can be determined precisely. The number of work unit k in repairable k/n (G) system is obtained precisely. The reliability of whole life cycle of repairable k/n (G) system can be predicted and guaranteed in the design period. Finally, it is illustrated that the proposed model is feasible and gives reasonable prediction.

• Journal of Computing Science and Engineering
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• v.7 no.3
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• pp.147-158
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• 2013

This invited paper introduces results on Web science and technology obtained during work with the Korea Advanced Institute of Science and Technology. In the first part, we discuss algorithms for exploring the deep Web, which refers to the collection of Web pages that cannot be reached by conventional Web crawlers. In the second part, we discuss sorting algorithms on the MapReduce system, which has become a dominant paradigm for massive parallel computing.

• Smart Structures and Systems
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• v.14 no.4
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• pp.559-567
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• 2014

The model of unit dynamic reliability of repairable k/n (G) system with unit strength degradation under repeated random shocks has been developed according to the stress-strength interference theory. The unit failure number is obtained based on the unit failure probability which can be computed from the unit dynamic reliability. Then, the transfer probability function of the repairable k/n (G) system is given by its Markov property. Once the transfer probability function has been obtained, the probability density matrix and the steady-state probabilities of the system can be retrieved. Finally, the dynamic reliability of the repairable k/n (G) system is obtained by solving the differential equations. It is illustrated that the proposed method is practicable, feasible and gives reasonable prediction which conforms to the engineering practice.

• Computers and Concrete
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• v.24 no.5
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• pp.437-444
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• 2019

PLC and its expansion module, electric ball valve and cooling pipe, electric heating steel plate and various components of the system, which is used to control test and process data. By automatically adjusting the opening of the valve, the system makes the top temperature and cooling speed develop along the ideal temperature diachronic curve. Moreover, the system enables the temperature difference between inside and surface of test block limited in a given range by automatically controlling the surface board heating. The method of physical simulation test by sandbox with built-in cooling water pipe and heating rod is adopted. On the premise of a given standard value, the operation of the system is checked under different working conditions. Further, an extension of this system is proposed, which enables its application to obtain some thermal parameters when cooperating with numerical simulation.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1899-1902
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• 2002

KEPCO is planning to operate 765kV Sin-Tao-Back and Sin-Ga-Pyong substations from 2004. A preventive diagnostic system to obtain the reliability of transformer and GIS is being adopted in 765kV substations. KEPRI has developed a preventive diagnostic system for 765kV substation since 1997. The preventive diagnostic system developed in that project was installed to the 345kV Eui-Ryung substation in June, 2000, and it is under circumstance durability test and operation capacity tests. In this paper, we analyze data of the preventive diagnostic system in 345kV Eui-Ryung substation.

• Journal of Power Electronics
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• v.15 no.4
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• pp.886-898
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• 2015

The design feasibility of a micro unidirectional DC transmission system based on an input-parallel output-parallel (IPOP) converter is analyzed in this paper. The system consists of two subsystems: an input-parallel output-series (IPOS) subsystem to step up the DC link voltage, and an input-series output-parallel (ISOP) subsystem to step down the output voltage. The two systems are connected through a transmission line. The challenge of the delay caused by the communication in the control system is addressed by introducing a ring communication structure, and its influence on the control system is analyzed to ensure the feasibility and required performance of the converter system under practical circumstances. Simulation and experiment results are presented to verify the effectiveness of the proposed design.