• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.1
• /
• pp.86-95
• /
• 2014

Productivity improvement of a shipbuilding company depends on how efficiently its limited resources are managed and utilized. Recently, research on modeling and simulation (M&S) to support shipyard production management system has been being under study. The production management based on M&S rejects decision making on experience, and it can establish productivity improvement method based on quantitative and specific data. In this paper, M&S is applied to the long-term plan as a part of the production planning in shipyards. To this end, the long-term plan processes and related management systems are analyzed. Based on the analysis, a simulation model and an application system using commercial simulation software are suggested. And basic structure of the suggested system is based on web technology such as Rich Internet Application, web services protocol for compatibility with existing shipyard enterprise systems. Utilizing the results of this study, it is expected that shipyard production planners can settle down work flow, in which one can establishes the production plan, simulates the plan, and analyzes the results, enabling a more reliable production plans.

• Journal of Korean Society of Archives and Records Management
• /
• v.18 no.1
• /
• pp.129-154
• /
• 2018

It is time to prepare for the imminent development from the field of records management through decentralization to the records management of the new age in accordance with the flow of decentralization. To overcome a centralized record management system, more archives should be established to realize autonomous and decentralized records management. In accordance with the shift to a full-scale electronic record management environment, the appropriateness and effectiveness of the three-phase system of processing-archival-permanent record management based on physical transfer should be reviewed in terms of transfer cost and work efficiency. The archives should function as institutional archives to carry out the continuous volume record management and the autonomous record management at the institution level. This study examined the possibilities and implications of the archives to expand their functions as archives of institutions for the decentralization of record management and information governance orientation. In addition, the study diversified the types of records management institutions as a way to accomplish this and determined a way to design the functions of archives that integrate the current-end-end-end records management. At each level, institutions should set up archives based on their circumstances and aim at information governance at the level of each archive. Moreover, each archive level should establish a horizontal network to govern record information management.

• Journal of the Optical Society of Korea
• /
• v.19 no.6
• /
• pp.705-710
• /
• 2015

The fabrication process of thin boron-doped nanocrystalline diamond (B-NCD) microelectrodes on fused silica single mode optical fiber cladding has been investigated. The B-NCD films were deposited on the fibers using Microwave Plasma Assisted Chemical Vapor Deposition (MW PA CVD) at glass substrate temperature of 475 ℃. We have obtained homogenous, continuous and polycrystalline surface morphology with high sp³ content in B-NCD films and mean grain size in the range of 100-250 nm. The films deposited on the glass reference samples exhibit high refractive index (n=2.05 at λ=550 nm) and low extinction coefficient. Furthermore, cyclic voltammograms (CV) were recorded to determine the electrochemical window and reaction reversibility at the B-NCD fiber-based electrode. CV measurements in aqueous media consisting of 5 mM K₃[Fe(CN)₆] in 0.5 M Na₂SO₄ demonstrated a width of the electrochemical window up to 1.03 V and relatively fast kinetics expressed by a redox peak splitting below 500 mV. Moreover, thanks to high-n B-NCD overlay, the coated fibers can be also used for enhancing the sensitivity of long-period gratings (LPGs) induced in the fiber. The LPG is capable of measuring variations in refractive index of the surrounding liquid by tracing the shift in resonance appearing in the transmitted spectrum. Possible combined CV and LPG-based measurements are discussed in this work.

• Journal of the Korean Chemical Society
• /
• v.11 no.4
• /
• pp.150-158
• /
• 1967

When anthracite burns by natural draft the mole percent of carbon monoxide (CO%) contained in exhaust gas is approximately expressed as follows in the early stage of combustion. (CO%)=$\frac{2{\alpha}}{1+{\alpha}}(CO_2%)$ exp $[-\vec{k}(No_2-Nc)^{1/2}{\tau}]$ where ${\alpha}=\frac{-0.395K_p+\sqrt{0.156K^2_p+(0.83+0.21K_p)K_p}}{0.83+0.21K_p}$ and $logK_p =-\frac{8593}{T} + 2.45logT -1.08{\times}10^{-3}T + 1.12{\times}10^{-7}T^2+2.77\vec{k},\;No_2$ and $N_c$ are the rate constant for the reaction ($CO+\frac{1}{2}O_2{\to}CO_2$), mole fraction of oxygen and oxides of carbon contained in the exhaust gas, respectively. From experimental evidence obtained in this work with natural draft combustion of briquettes the percent of carbon monoxide to the total quantity of oxides of carbon produced and rate of air flow into the furnace were: 1.76% and 0.53 l/sec (When lid is used in the furnace) 12.35% and 2.4 l/sec (without use of a lid). is the rate constant for the reaction($CO+\frac{1}{2}O_2{\to}CO_2$) and $N_0,\;and\;N_c$ are respectively the molefraction of oxygen and oxide of carbon contained in the exhaust gas.

• Clean Technology
• /
• v.13 no.1 s.36
• /
• pp.34-45
• /
• 2007

Phase behavior of the ternary systems of water-insoluble simvastatin drug, which is well known to be effective drugs for hypercholesterolemia therapy, in solvent mixtures of dichloromethane and supercritical carbon dioxide was investigated to present a guideline of establishing operating conditions in the particle formation of the drugs by a supercritical anti-solvent recrystallization process utilizing dichloromethane as a solvent and carbon dioxide as an anti-solvent. The solubilities of simvastatin in the mixtures of dichloromethane and carbon dioxide were determined as functions of temperature, pressure and solvent composition by measuring the cloud points of the ternary mixtures at various conditions using a high-pressure phase equilibrium apparatus equipped with a variable-volume view cell. The solubility of the drug increased as the dichloromethane composition in solution and the system pressure increases at a fixed temperature. A lower solubility of the drug was obtained at a higher temperature. The second half of this work is focused on the particle formation of the simvastatin drug by a supercritical anti-solvent recrystallization process in a cylindrical high-pressure vessel equipped with an impeller. Microparticles of the simvastatin drug were prepared as functions of pressure (8 MPa to 12 MPa), temperature (303.15 K, 313,15 K), feed flow rate of carbon dioxide, and stirring speed (up to 3000 rpm), in order to observe the effect of those process parameters on the size and shape of the drug microparticles recrystallized.

• Journal of Digital Convergence
• /
• v.10 no.11
• /
• pp.427-432
• /
• 2012

The article herein suggested a compound repository and a descriptive method to develop a compound knowledge process. A data target saved in a compound knowledge repository suggested in this article includes all compound knowledge meta data and digital resources, which can be divided into the three following factors according to the purpose: user roles, functional elements, and service ranges. The three factors are basic components to describe abstract models of repository. In this article, meta data of compound knowledge are defined by being classified into the two factors. A component stands for the property about a main agent, activity unit or resource that use and create knowledge, and a context presents the context in which knowledge object are included. An agent of the compound knowledge process performs classification, registration, and pattern information management of composite knowledge, and serves as data flow and processing between compound knowledge repository and user. The agent of the compound knowledge process consists of the following functions: warning to inform data search and extraction, data collection and output for data exchange in an distributed environment, storage and registration for data, request and transmission to call for physical material wanted after search of meta data. In this article, the construction of a compound knowledge repository for recommendation system to be developed can serve a role to enhance learning productivity through real-time visualization of timely knowledge by presenting well-put various contents to users in the field of industry to occur work and learning at the same time.

• Solar Energy
• /
• v.15 no.3
• /
• pp.3-14
• /
• 1995

The Direct Contact heat Exchanger(DCHX) has been widely studied in the chemical industry for many years due to its inherent simplicity as a counter-current divice for heat and mass transfer. In many solar systems, the DCHX unit can be combined with the thermal storage unit, or alternatively, it can be used separately from the storage unit, much like an external(to storage) closed heat exchanger system. In the present work, the spray column type of direct contact heat exchangers are studied extensively to harness the solar energy for hot water and spaced heating. Some of the major considerations that are involved in the design of heat exchangers in this study are that : working fluid is a hydrocaabon(such as Texaterm) or water which is either lighter or heavier than storage medium. The experimental data have revealed some interesting characteristics concerning the application of DCHXs for solar energy utilization. These experiments are carried out in the line of solar heating system, major results are as follows : 1) the flow and aspect of working fluid drop for maxium heat transfer 2) efficiency and volumetric heat transfer coefficient of D.C.H.X with a heavier working fluid are higher than those of D.C.H.X with a lighter working fluid.

• Journal of the Korean Geophysical Society
• /
• v.3 no.2
• /
• pp.113-126
• /
• 2000

We have conducted multiple geophysical surveys to investigate the geoenvironmental change of the Nanjido Landfill due to the stabilization process. Geophyscial surveys are comprized of gravity, magnetic, dipole-dipole electrical and SP methods. Due to the field conditions, surveys were conducted on the top surface of the landfill no.2 and southern border areas in front of landfills. The gravity anomalies obtained on the top surface of the landfill no.2 in 1999 show that the gradient of the anomaly on the central area is decreasing in comparison with that observed four years ago. The complexity of magnetic anomaly pattern it also decreasing. These facts suggest that the stabilization work of the Nanjido landfill makes some progress by compaction process due to repetitive subsidence and refilling. The dipole-dipole electrical resistivity and SP data obtained on the outside of the waterproof wall at the landfill no.1 were severely affected by unsatisfactory surface conditions. On the other hand, the dipole-dipole electrical resistivity profiles obtained on the inside and outside parts of the waterproof wall at the landfill no.2 show the blocking effect of leachate flow by the waterproof wall. Few SP anomalies are observed on the top and side surfaces of the landfill no.2, but SP anomalies obtained on the base area inside the waterproof wall strongly reflect the effect of leachate collecting wells.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.10 no.4
• /
• pp.1-10
• /
• 2011

According to the worldwide efforts to reduce greenhouse gases consequent upon climatic change, the field of road traffic is also making diverse efforts to reduce the emissions of greenhouse gases. Among these, the exhaust gases from vehicles, the so-called main culprit of the greenhouse gases will take place the more as delay and tie-up of vehicles ever take place. Accordingly, as a scheme for reducing the delay & tie-up of vehicles, it's possible to bring up the idea of supply of new facilities and management of the existing facilities; recently, a lot more focus is being put on the management of the existing facilities due to enormous amounts of construction cost. In the midst of growing concern for traffic demand management policy, it's about the time we should do research on the tollbooth metering on the expressway whose research is almost non-existent home and abroad. As a traffic demand management policy coming to happen in case of the management of pay expressway like Japan and Korea, this research analyzed the contents of tollbooth metering, its effect and its subsequent convenience. Especially as a tool for effect analysis, this research made an analysis using VISSIM-a micro-simulation tool. As the tollbooth metering promoted, as a part of green traffic promotion strategy, is expected to contribute to improvement in traffic flow and reduction in carbon emissions, etc. It seems that there needs to be continuous research work on the management plan & revitalization plan for maximization of its effect later as well.

• Journal of the Korean Institute of Gas
• /
• v.18 no.4
• /
• pp.63-67
• /
• 2014

Fischer-Tropsch synthesis mainly produces a wax which is a viscous liquid for long carbon chain. When a catalytic fixed-bed reactor is used for Fischer-Tropsch synthesis, the wax generated on a catalyst surface can keep adsorbing on the catalyst surface. This liquid hold-up causes significant pressure drop and clogging problems through the reactor. Thus, the model for liquid hold-up is required to design the size of reactor and catalyst particles. In this study, the liquid hold-up model considering structural and operational conditions was proposed based on empirical equations for convective mass transfer between the syngas flow and the wax-adsorbed catalyst. The developed model was validated by comparing with the experimental data from Knochen's work (2010). The influence of reactor length and coross section on the wax hold-up in reactor were analyzed and the optimal reactor size were proposed.