• Journal of Advanced Marine Engineering and Technology
• /
• v.26 no.3
• /
• pp.375-381
• /
• 2002

Measuring of the dissolved oxygen is widely used for the environmental control of natural waters, sewage waste treatment, medical and biochemical studies, soil husbandry, food and drug process control, and prevention of corrosion in boilers. Especially, a power plants need special management for preventing accidents from corrosion, therefore, it is essential to measure the concentration of dissolved oxygen in real-time. In this paper we present a method of measuring dissolved oxygen very accurately up to pub units. This method, called polarograph method, is based on the measures of the electric current generated by the oxidation process in cathode and de-oxidation process in anode, assuming that the amount of the current is proportional to the density of dissolved oxygen.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.19 no.2
• /
• pp.106-110
• /
• 1983

As the first step to investigate the effect of ship's motion when detecting target with an echo sounder, variations in the incident sound level at the optional position within the sound beam due to roll motion of the transmitter have been measured and calculated. In this experiment, the transmitter (75 KHz) was mounted to the bottom of a FRP model of the 2,275 G. T. stern trawler and the receiver (75 KHz) was installed at each measuring point within the transmitter's beam. Then, the incident sound level was measured for the roll angles from the free roll test on the model ship. For a range of roll angle of $\pm$20$^{\circ}$from the vertical, the measuring values of the incident sound level at each measuring point were rapidly fluctuated from 12.9% to 78.1 depending on the roll angle, and agreed well with the caculated ones. Consquently, we concluded that the effect of ship's motion when detecting target with an echo sounder should be sufficiently considered.

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2006.06a
• /
• pp.65-66
• /
• 2006

As industrial technology recently, a field of marine engineering is demanding integration and manless system. In this study, tank monitoring system is developed, which is able to watch real-time the marine tank for measuring a level, pressure, temperature. The system will provide efficiently measuring data for operator.

• Journal of Korea Foundry Society
• /
• v.25 no.2
• /
• pp.73-79
• /
• 2005

Effects of Cr and Ni addition on damping capacity, mechanical property, and corrosion resistance of Fe-17%Mn martensitic alloy have been studied. Martensite start temperature($M_{S}$) of the alloy decreases linearly with increasing Cr and Ni contents up to 15%. The damping capacity decreases gradually from 27 to 22% in specific damping capacity(SDC) with increasing Cr and Ni contents from zero to 10%, and decreases rapidly with further Cr and Ni content in Fe-17%Mn alloy. The tensile strength of the alloy maintains a level of 60 $kgf/mm^{2}$ regardless of Cr content with an elongation of 20 to 25%. But, in case of Fe-17%Mn-x%Ni alloy, the tensile strength decreased rapidly with the Ni content of above 10% because of austenite morphology. Immersion test in 5% NaCl solution leads to the result that the corrosion resistance of the alloy becomes excellent above 10% Cr. From the above results, it is concluded that the optimum Cr content to improve the mechanical property and corrosion resistance of the alloy in 5%NaCl solution with a lesser decrease in damping capacity is about 10%. In the case of 5% $H_{2}SO_{4}$ condition, the Fe-17%Mn-10%Ni is an optimum alloy.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.3 no.3
• /
• pp.59-66
• /
• 1980

The purpose of this paper to study on measuring method in technical progress. Technology is combination method of raw material and capital, land, labour. The first step to technical Progress is COBB-DOUGLAS production function, so technical progresses are important role in economic growth and development. General production function from Y=f(K, L, T) and COBB-DOUGLAS production function Y=${AK^I}{L^b}$ is first condition. Technical progress is saving of production factor In capital saving, labour saving, neutral saving. Marred Hicks Robinson has Insist on technical progress by each view of production factor, but, what is most excellent measuring method of technical progress\ulcorner I : productivity index method. II : Gross Production function method. Productivity method used in every products level in weight values, gross method function method used in production factor attributed to products. Above two measuring method has delicate problem in each input factor, substitution relation and production factor simultaneously linked each others This basic problem based on technical progress is not solubable in this time.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.31-31
• /
• 2023

During December 2022, the northeast monsoon, which dominates the south and the Gulf of Thailand, had significant rainfall that impacted the lower southern region, causing flash floods, landslides, blustery winds, and the river exceeding its bank. The Golok River, located in Narathiwat, divides the border between Thailand and Malaysia was also affected by rainfall. In flood management, instruments for measuring precipitation and water level have become important for assessing and forecasting the trend of situations and areas of risk. However, such regions are international borders, so the installed measuring telemetry system cannot measure the rainfall and water level of the entire area. This study aims to predict 72 hours of water level and evaluate the situation as information to support the government in making water management decisions, publicizing them to relevant agencies, and warning citizens during crisis events. This research is applied to machine learning (ML) for water level prediction of the Golok River, Lan Tu Bridge area, Sungai Golok Subdistrict, Su-ngai Golok District, Narathiwat Province, which is one of the major monitored rivers. The eXtreme Gradient Boosting (XGBoost) algorithm, a tree-based ensemble machine learning algorithm, was exploited to predict hourly water levels through the R programming language. Model training and testing were carried out utilizing observed hourly rainfall from the STH010 station and hourly water level data from the X.119A station between 2020 and 2022 as main prediction inputs. Furthermore, this model applies hourly spatial rainfall forecasting data from Weather Research and Forecasting and Regional Ocean Model System models (WRF-ROMs) provided by Hydro-Informatics Institute (HII) as input, allowing the model to predict the hourly water level in the Golok River. The evaluation of the predicted performances using the statistical performance metrics, delivering an R-square of 0.96 can validate the results as robust forecasting outcomes. The result shows that the predicted water level at the X.119A telemetry station (Golok River) is in a steady decline, which relates to the input data of predicted 72-hour rainfall from WRF-ROMs having decreased. In short, the relationship between input and result can be used to evaluate flood situations. Here, the data is contributed to the Operational support to the Special Water Resources Management Operation Center in Southern Thailand for flood preparedness and response to make intelligent decisions on water management during crisis occurrences, as well as to be prepared and prevent loss and harm to citizens.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.1
• /
• pp.1-5
• /
• 2011

The brand-new small output radio equipment which is over than 800MHz has an all-in-one interior antenna. We suggested new measuring method and developed related equipment because all-in-one radio equipment's performance evaluation requests old way, which is measuring transmitter output and antenna capacity separately, to be changed. That is, origin of small radio equipments with the 360 degree field measured by measuring the TRP, and also 360 degree opposite reception level measured at the radio equipment by measuring the TIS to make a quantitative evaluation was to be. Furthermore, we made managing frequencies, all-in-one radio equipment's best design and capacity management efficiently by measuring the gain of an antenna mounted on a PCB, the circuit around the genetic material, conductive material on the effects of radiation or the reception level.

• Korean Management Science Review
• /
• v.20 no.2
• /
• pp.95-111
• /
• 2003

The standard issue in the information and telecommunication industry is increasingly important with the rapid development of technology. This paper proposes an index model which can measure the degree of standardization in the Korean information and telecommunication field. We first classified ICT sector into 14 sub-sectors. Then for each sub-sector, we considered a set of important determinants to measure the level of standardization, and constructed a linear equation using this set of determinants. Finally we estimated the relative degree of importance of each determinant using the AHP methodology. The proposed model found that overall level of standardization in the Korean ICT industry is relatively low, and ‘IMT-2000 technology’ and ‘computer network technology’ among 14 sub-sectors are highly standardized sub-sectors. The validity of the proposed model was also partially proved using two different methods, holistic and historical approach.

• Journal of Environmental Science International
• /
• v.23 no.4
• /
• pp.615-623
• /
• 2014

The groundwater level varies according to the characteristics and composite materials of aquifer. In this study, specific yield and reaction factor which are the major two hydrogeological parameters in the WTF(Water Table Fluctuation) method were estimated and analyzed spatial characteristics. 8 groundwater level stations which have enough measuring period and high correlation with rainfall in the Hancheon watershed were used. The results showed that specific yield was randomly distributed and reaction factor showed inverse trend with altitude. If the enough data were collected, reaction factor according to altitude in ungauged points could be estimated by using these parameter characteristics.

• Journal of Industrial Technology
• /
• v.9
• /
• pp.43-49
• /
• 1989

In this study, 3-point bending test for the mode I state and 4-point shear test for the mode II state were adopted to verify the crack initiation load level through comparing the test results of the acoustic emission and the ASTM testing criteria, using Jecheon granite, as the rock sample. The major result obtained in this study is that the crack initiation load levels obtained by using ASTM testing criteria and by measuring acoustic emissions showed analogous, roughly. However in case of demanding high safety, the crack initiation load level needs to be underestimated to the level that the crack begins to deform nonlinearly.