• Journal of the Society of Naval Architects of Korea
• /
• v.59 no.6
• /
• pp.362-371
• /
• 2022

As considerable interests in noise emission from the ships have been increased, International Maritime Organization (IMO) standardized the Underwater Radiated Noise (URN) measurement process of commercial ships in deep seas by enacting the related ISO standard ISO 17208-1 and classification societies responded with the enactment or revision of corresponding notations. According to this trend, a new hybrid underwater sound propagation model based on underwater sound propagation theories was developed and its accuracy on analysis was verified through the result comparison with the results of other generally used models. Using the verified model, each URN propagation characteristics adjusted by the correction methods proposed in the ISO standard and class notations were analyzed and compared in two assumed URN measurement cases. The results showed that the effects of transmission loss corrections in the circumstances with less bottom reflections generally similar but they had rather large differences in the model analysis results with bottom-reflection-dominant conditions. It was concluded that the deep consideration of effective bottom-reflection-correction method should be made in future revisions of ISO standard and class notations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.31 no.2
• /
• pp.122-127
• /
• 2018

In an attempt to estimate the life projection of LED packages, IESNA published a paper regarding an LED package measurement test method in 2008, and a life projection technical document in 2011, to be used for LED life estimation. IESNA's publications regarding LED package measurement methods were functional, but they were not internationally standardized before 2017. In order to develop a standardized method, the International Standard chose to use the LM-80 as a measurement method for LED life projection in their publication in 2017. Many projection methods have been discussed by the IEC Technical Committee 34 working group, including the method using an exponential function, which reflects lumen degradation characteristics well. This study is designed to explore alternative LED package life estimation methods using an exponential function with statistical analysis, other than the one suggested by the International Standard.

• Journal of the Korea Institute of Building Construction
• /
• v.2 no.3
• /
• pp.155-162
• /
• 2002

The Ministry of Construction-Transportation released a plan about EVMS in 1993 in order to prepare measures for an efficient public construction project, and prepared an enforcement proposal concretely in June for 2000 years, and have enforce a public project by an example with a target. Therefore, accurate analysis and evaluation about field progress are required for efficient management of a building construction, and must be established building construction management system for fast action about a problem However, unified management cannot be consisting because a work progress system is different from details estimate system within a country. and There is not still a definite standard in progress measurement for an application of EVMS. A purpose of this study is to present an improvement about a problem of progress measurement for an application of EVMS. The contents of a study, inquired into a progress measurement method and a standard to use in the field of a public construction and private construction and Checks a problem and presented an improvement item necessary for and is as follows. $\circled1$ must establishes a control account and progress measurement standard. $\circled2$ must manage progress in a activity viewpoint. $\circled3$ must use an accurate CPM process management technique.

• Journal of Environmental Science International
• /
• v.7 no.2
• /
• pp.203-208
• /
• 1998

A simple on-line measurement system consisting of a conventional peristaltic pump, a HPLC-type heater, and a flow-through spectrophotometer is introduced for the determination of chemical oxygen demand(CODI. The system was configured such that the reaction mixture in the highly concentrated surffuric acrid medium flowing through the PTFE reaction tubing was heated at 150℃ and the absorbance of dichromate was continuously moutored at 445 m. The same addation principle as in the standard procedure was employed akcept the use of CoSO4 as a new effective catalyst. To test the system, potassium hydrogen phthalate was selected as a COD standard material. With suitably optimized reaction condition, the applicable concentration range depends on the concentration of potassium dichromate in the oxidizing reagent. With 2.0×10-3 M and 5.0×10-4M dichromate, the linear dynamic range was observed up to 400 ppm and 100 ppm, respectively. The standards in the Unear ranges were shown to be completely oxidized, which was confirmed with sodium oxalate or Mohr's salt. In all cases, the typical reproduclbility for betweenruns was 2% or less. The proposed measurement system provides the valuable in- formation for the further development of automated analysis system based on the present standard procedure.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.3_4
• /
• pp.377-386
• /
• 2004

This report is the second study to develop the standard tables of body measurements to be used for improving the fit of garments and patterns for women aged 60 and older. The purpose of this study is to suggest the new sizing system proper to the women aged 60 and older by classifying their somatotype and developing the standard tables of body measurements for each somatotype. The data are the anthropometric measurements of 329 women aged 60 and older measured in 2001 and the 1997 National Somatometry Survey data. The major contents of this study are as follows. The applicability of KS K 0051 and ISO 3637 sizing systems to the women aged 60 and older was investigated by analyzing the distribution of height and drop index the difference of hipgirth and bustgirth. In this result, we certified the two sizing systems were not so proper to elderly women and the new sizing system proper to them was required. So, we classified the somatotype of the women aged 60 and older to 3 groups, 135cm$\leq$H(height)＜145cm, 145cm$\leq$H＜155cm, 155cm$\leq$H＜165cm by height and classified to 3 groups, -4cm$\leq$D(drop)＜16cm, -4cm$\leq$D＜4cm, -l6cm$\leq$D＜-4cm by drop index, and we suggested more proper sizing system for women aged 60 and older by compounding height and drop groups. We also developed the standard tables of body measurements every bustgirth groups of 9 somatotypes. We expect the standard tables of body measurements to applicate to manufacture clothing for elderly women.

• Journal of the Korean Society for Library and Information Science
• /
• v.37 no.4
• /
• pp.131-149
• /
• 2003

Scientific/technical data whose reliability is authorized have to include physical/chemical constants, authorized property value or authorized scientific statistical values so that the scientists in the same field use them continuously and repeatedly for their research. The data also have to be managed as Standard Reference Data that will be used in other area nationwide by analyzing, evaluating and authorizing the accuracy and reliability of the information with scientific methods. This study suggests a plan for establishing the National Center for Standard Reference Data as well as a necessity for managing the data produced in research process as a national Standard Reference Data. Also, a prototype of research information system for measurement standards is developed and described in detail for research information for measurement standard to be used as a reference data, then a plan to managing national reference data is suggested, in addition.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.5B no.3
• /
• pp.283-288
• /
• 2005

A portable primary inductance standard set that includes a Maxwell-Wien bridge and a 10 mH standard inductor installed in a thermostat has been developed at KRISS. Two auxiliary resistance capacitance networks (analogous to a 'Wagner ground') provide excellent stability of the bridge balance and impose less strict requirements on the components of these networks. Removable capacitance and ac-dc resistance standards used in the bridge arms made it possible to reproduce 10 mH and 100 mH inductance values in the frequency range of 500 Hz to 3 kHz. From investigations of this standard and preliminary comparison with VNIIM (D. I. Mendeleyev Institute for Metrology), the results have demonstrated that the bridge can be used as a part of the transportable inductance standard with a measurement uncertainty within (1-3) $\mu$H/H at frequencies of 1 kHz and 1.6 kHz. The application of the bridge as a constituent part of the transportable standard gives us an opportunity to eliminate the influence of the standard inductors.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.27 no.8
• /
• pp.1071-1080
• /
• 2003

A national standard system was developed in order to calibrate and test the oil flowmeters for the petroleum field. A stop valve and a gyroscopic weighing scale were employed for the primary standard of the flow quantity. It is operated by the standing start and finish mode and the static weighing method. The model equation for uncertainty evaluation was based on the calibration principle of standard system. The sources of the uncertainties were quantified and combined according to the GUM(Guide to the Expression of Uncertainty in Measurement). It was found that the standard system had the relative expanded uncertainty of 0.04 % in the range of 18 - 350 ㎥/ｈ. According to the uncertainty budget, the uncertainties of the fluid density and the volume of pipeline, which were temperature dependent, contributed 92% of final uncertainty in the oil flow standard system.

• The Journal of Korean Society for Radiation Therapy
• /
• v.9 no.1
• /
• pp.71-81
• /
• 1997

I. Objective and Importance of the Project We have been using MC-50 cyclotron and NT-50 neutron therapy machine for treating cancer patients since 1986 at Korea Cancer Center Hospital. It is mandatory to measure accurately the dose distribution and the total absorbed dose of fast neutron for putting it to the clinical use. At present the methods of measurement of fast neutron are proposed largely by American Associations of Physicists in Medicine (Task Group 18), European Clinical Neutron Dosimetry Group, and International Commission on Radiation Units and Measurements. The complexity of measurement, however, induce the methodological differences between them. In our study, therefore, we tried to establish a unique technique of measurement by means of measuring the emitted doses and the dose distribution of fast neutron beam from neutron therapy machine, and to invent a standard method of measurement adequate to our situation. II. Scope and Contents of the Project For establishing a unique technique of measurement and inventing a standard method of measurement of fast neutron beam, 1. to grasp the physical characteristics of neutron therapy machine 2. to study the principles for measrement of fast neutron beam 3. to get the dose distribution (dose rate, percent-depth dose, flatness etc) throught the actual measurement 4. to compare our data with those being cited world-widely.

• Tunnel and Underground Space
• /
• v.12 no.4
• /
• pp.268-276
• /
• 2002

In this study, a 3D coordinate measurement system equipped with a laser displacement meter for digitizing rock joint surface was established and the digitized data were used to calculate several roughness parameters. The parameters used in this study were micro avenge inclination $angle(i_{ave})$, average slope of joint $asperity(SL_{ ave})$, root mean square of $i-angle(i_{rms})$, standard deviation of height(SDH), standard deviation of $i-angle(SD_i)$, roughness profile $index(R_P)$, and fractal dimension(D). The relationships between the roughness parameters based on the digitzation of the surface profile were analyzed. Since the measured value varied according to the degree of reflection and the variation of colors at the measuring point, rock joint surface was painted in white to minimize the influence of the surface conditions. The comparison of the measured values and roughness parameters before and after painting revealed the better consequence from measurement on the painted surfaces. Also, effect of measuring interval was studied. As measured interval was increased, roughness parameters were exponentially decreased. The incremental sequence of degree of decrease was $SDH\; i_{ave},\; i_{rms},\; SD_i,\;and\; R_ p-1$. As a result of comparison of parameters from pin-type measurement system and laser type measurement system, all value of parameters were higher when laser-type measurement system was used, except SDH.