• Journal of the Korean Society of Safety
• /
• v.11 no.2
• /
• pp.150-159
• /
• 1996

In this paper, an A-team(Asynchronous Team ) based approach for Reactive power and volage control considering static security assessment in a power system with infrastructural deficiencies is proposed. Reactive power and voltage control problem is the one of optimally establishing voltage level given several constraints such as reactive generation, voltage magnitude, line flow, and other switchable reactive power sources. It can be formulated as a mixed-integer linear programming(MILP) problem without deteriorating of solution accuracy to a certain extent. The security assessment is to estimate the relative robustness of the system in Its present state through the evaluation of data provided by security monitoring. Deterministic approach based on AC load flow calculations is adopted to assess the system security, especially voltage security. A security metric, as a standard of measurement for power system security, producting a set of discrete values rather than binary values, is employed. In order to analyze the above two problems, reactive power/voltage control problem and static security assessment problem, in an integrated fashion for real-time operations, a new organizational structure, called an A-team, is adopted. An A-team is an organization for agents which ale all autonomeus, work in parallel and communicate asynchronously, which is well-suited to the development of computer-based, multi-agent systems for operations. This A-team based approach, although it is still in the beginning stage, also has potential for handling other difficult power system problems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.1
• /
• pp.1013-1016
• /
• 2005

ZnO nanostructure was fabricated by catalyst-free method using Zn powder in air. The growth temperature was controlled from 450$^{\circ}$C to 600$^{\circ}$C, and the structural and optical properties were investigated by scanning electron microscopy (SEM), photoluminescence (PL), energy dispersive X-ray spectroscopy (EDX) and cathodoluminescence (CL). From all samples both ZnO tetrapods and clusters were observed. No significant dispersion was observed from the ZnO tetrapods, however, ZnO clusters show considerable change in density and size. From the EDX results, atomic composition difference was found. The clusters have O-deficiencies, while tetrapods have stoichiometric composition. Strong luminescence was observed at room temperature. From room temperature PL, UV emission at 380 nm and green emission at 500 nm were observed, and the intensity ratio ($I_{uv}/I_{green}$) increased as growth temperature increases. CL measurements show that the UV emission is closely related with tetrapods and the green emission is dominated from the clusters.

• Journal of KIISE:Software and Applications
• /
• v.33 no.7
• /
• pp.589-604
• /
• 2006

Software product lines (SPL) are recently an emerging software reuse paradigm, which helps organizations develop their products from reusable core assets rather than from scratch. For developing these assets, understanding commonality and variability (C&V) is essential. A feature-oriented approach has been used extensively for C&V analysis in the SPL. However, this contains no proposal to systematically identify features and provide the rationale for the features. Further, the approach does not directly show how the results of C&V analysis will satisfy an organization's high-level business goals and provide the rationale for the C&V. Therefore, this paper presents a domain analysis method for the SPL based on goals, scenarios, and features in order to overcome some of the deficiencies and limitations of the feature-oriented approach. In particular, the paper proposes a domain requirements model (DRM) and a domain requirements modeling method based on the DRM. This method has been applied to the home integration system (HIS) domain to demonstrate its feasibility with a supporting tool, namely IDEAS. Our approach makes it possible to systematically identify the features and provide the rationale for both the features and the C&V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.25 no.10
• /
• pp.805-810
• /
• 2012

Transparent conducting oxides (TCOs) have wide range of application areas in transparent electrode for display devices, Transparent coating for solar energy heat mirrors, and electromagnetic wave shield. $SnO_2$ is intrinsically an n-type semiconductor due to oxygen deficiencies and has a high energy-band gap more than 3.5 eV. It is known as a transparent conducting oxide because of its low resistivity of $10^{-3}{\Omega}{\cdot}cm$ and high transmittance over 90% in visible region. In this study, co-doping effects of Al and Y on the properties of $SnO_2$ were investigated. The addition of Y in $SnO_2$ was tried to create oxygen vacancies that increase the diffusivity of oxygen ions for the densification of $SnO_2$. The addition of Al was expected to increase the electron concentration. Once, we observed solubility limit of $SnO_2$ single-doped with Al and Y. $\{(x/2)Al_2O_3+(x/2)Y_2O_3\}-SnO_2$ was used for the source of Al and Y to prevent the evaporation of $Al_2O_3$ and for the charge compensation. And we observed the valence changes of aluminium oxide because generally reported of valence changes of aluminium oxide in Tin - Aluminium binary system. The electrical properties, solubility limit, densification and microstructure of $SnO_2$ co-doped with Al and Y will be discussed.

• Applied Microscopy
• /
• v.34 no.2
• /
• pp.113-120
• /
• 2004

Microstructural characteristics of the Complex Perovskite (1-x) $(Li_{1/2}Sm_{1/2})TiO_3-x (Na_{1/2}Sm_{1/2})TiO_3$ (LNST) system have been investigated using the transmission electron microscopy (TEM). When $0.0{\leq}x{\leq}0.6$, the vacancy ordering forming the 1/2 (001) superlattice reflections due to the A-site cation deficiencies has apperaed. It could be confirmed by presence of ABPs. But it was difficult to form the vacancy ordering since vacancy concentration gradually lowered as the amount of the substituted Li ions decrease. Antiphase boundaries (APBs) were presented in microstructures of LNST when $0.8{\leq}x{\leq}1.0$. It was considered that these boundaries were caused by the 1:1 chemical ordering of A-site cations, Na and Sm ions. LNST had not only the antiphase tilting of oxygen octahedron but also the inphase tilting of oxygen octahedron and the antiparallel shift of cations all of them. It could be confirmed by presence of ferroelastic domains

• Journal of KIISE:Software and Applications
• /
• v.31 no.2
• /
• pp.137-152
• /
• 2004

Assesment of 30 nutritional minerals and 8 toxic elements in hair are very important not only for determining adequacy, deficiencies and unbalance, but also for assessing their relative relationships in the body. A test has been developed that serves this purpose exceedingly well. This test is known as tissue mineral analysis(TMA). TMA is very popular method in hair mineral analysis for health care professionals in over 46 countries' medical center. However, there are some problems. First, they do not have database which is suitable for korean to do analyze. Second, as the TMA results from TEI-USA is composed of english documents and graphic files prohibited to open, its usability is very low. Third, some of them has low level database which is related to TMA, so hairs are sent to TEI-USA for analyzing and medical services. it bring about an severe outflow of dollars. Finally, TMA results are based on the database of american health and mineral standards, it is possibly mislead korean mineral standards. The purposes of this research is to develope the first Intelligent Medical Expert System(IMES) of TMA, in Korea, which makes clear the problems mentioned earlier IMES can analyze the tissue mineral data with multiple stage decision tree classifier. It is also constructed with multiple fuzzy rule base and hence analyze the complex data from Korean database by fuzzy inference methods. Pilot test of this systems are increased of business efficiency and business satisfaction 86% and 92% respectively.

• Tunnel and Underground Space
• /
• v.16 no.3 s.62
• /
• pp.251-258
• /
• 2006

In this paper, the applicability to the Korean rock condition of using the deformation moduli based on Rock Mass Rating (RMR) and Pressuremeter Test (PMT) is evaluated. The correlations among deformation moduli and various rock properties were also analyzed. It appears that the existing correlations using RMR overestimate the deformation moduli and wide variation was found between predicted moduli using these correlations and measured values. As for the correlations among the deformation moduli and various rock properties, Rock Quality Designation (RQD) and unconfined compressive strength (UCS) were found to correlate to deformation moduli reasonably well, but joint spacing and joint conditions appear to correlate poorly to RQD and UCS. Additionally, groundwater can not be correlated with the modulus values. While the depth has very little contribution to deformation modulus, it should be factored in the simple regression analyses with various rock mass properties, especially with the correlations made with UCS, RQD etc. With the deficiencies of these correlations, more in depth analysis techniques such as multivariate correlations may be to reliably estimate deformation modulus of rock mass.

• Journal of Life Science
• /
• v.15 no.6 s.73
• /
• pp.955-960
• /
• 2005

Resistance to metronidazole, a key component of therapies against Helicobacter pylori, is common in clinical isolates. Resistance generally requires inactivation of rdxA (HP0954), and sometimes also frxA (HP0642), two related nitroreductase genes. Here we studied the effect of resistance to metronidazole on fitness of the gastric pathogen H. pylori. The effect of metronidazole resistance for H. pylori in culture was assessed first by looking at colonies formed by freshly constructed mutant derivatives of H. pylori strain 26695. Mutations resulting in metronidazole resistance caused premature death of H.pylori in stationary phase, but had no significant effect on early exponential growth. The effect of nitroreductase deficiencies on fitness in vivo was tested by infecting C57BL/6 mice with 1:1 mixtures of SS1 wild type and its isogenic metronidazole resistant derivatives. Inactivation of rdxA caused an inability to colonize mice in SS1 H. pylori strain. Derivatives of a metronidazole resistant strain that survived better in stationary phase, although remaining metronidazole resistant, could again colonize mice. In conclusion, metronidazole resistance diminishes H. pylori's fitness, but their costs can be suppressed by additional mutation.

• Nutrition Research and Practice
• /
• v.10 no.1
• /
• pp.56-66
• /
• 2016

BACKGROUND/OBJECTIVES: Despite successes recorded in combating iodine deficiency, more than 2 billion people are still at risk of iodine deficiency disorders. Rural landlocked and mountainous areas of developing countries are the hardest hit, hence the need to explore and advance novel strategies such as biofortification. SUBJECTS/METHODS: We evaluated adoption, purchase, and consumption of iodine biofortified vegetable legumes (IBVL) using the theory of protection motivations (PMT) integrated with an economic valuation technique. A total of 1,200 participants from three land-locked locations in East Africa were recruited via multi-stage cluster sampling, and data were collected using two, slightly distinct, questionnaires incorporating PMT constructs. The survey also elicited preferences for iodine biofortified foods when offered at a premium or discount. Determinants of protection motivations and preferences for iodine biofortified foods were assessed using path analysis modelling and two-limit Tobit regression, respectively. RESULTS: Knowledge of iodine, iodine-health link, salt iodization, and biofortification was very low, albeit lower at the household level. Iodine and biofortification were not recognized as nutrient and novel approaches, respectively. On the other hand, severity, fear, occupation, knowledge, iodine status, household composition, and self-efficacy predicted the intention to consume biofortified foods at the household level; only vulnerability, self-efficacy, and location were the most crucial elements at the school level. In addition, results demonstrated a positive willingness-to-pay a premium or acceptance of a lesser discount for biofortification. Furthermore, preference towards iodine biofortified foods was a function of protection motivations, severity, vulnerability, fear, response efficacy, response cost, knowledge, iodine status, gender, age. and household head. CONCLUSIONS: Results lend support for prevention of iodine deficiency in unprotected populations through biofortification; however 'threat' appraisal and socio-economic predictors are decisive in designing nutrition interventions and stimulating uptake of biofortification. In principle, the contribution is threefold: 1) Successful application of the integrated model to guide policy formulation; 2) Offer guidance to stakeholders to identify and tap niche markets; 3) stimulation of rural economic growth around school feeding programmes.

• Journal of the Korean Institute of Gas
• /
• v.25 no.3
• /
• pp.1-8
• /
• 2021

Among the flare systems that handle discharged substances from safety valves, the knockout drum was a key facility for safety, but the installation standards were not clear, so it was necessary to review the standards acceptable to the workplace and regulatory agencies. After investigating the domestic and foreign technical standards of knockout drums and the deficiencies of previous studies, research was first conducted on the degree of mass discharge, the installation location of the intermediate knockout drum, and the effect of changes in the composition of the discharged material. As a result of the study under the process simulation conditions, the gas-liquid separation of the knockout drum was completed in a small amount of less than 7,500kg/hr. However, when more than that was released, the gas-liquid separation effect was small even with the addition of an intermediate knockout drum. In addition, when the composition ratio of the material easily condensed was increased (molar fraction 10%), the gas-liquid separation effect of the knockout drum increased in the case of mass release. The gas-liquid separation effect was analyzed to be greater when the knockout drum was installed adjacent to the stack than the knockout drum was installed adjacent to the process equipment.