• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.65-75
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• 2011

Power Line Communication (PLC) is a system for carrying data on a conductor used for electric power transmission. Recently, PLC has received much attention due to connection efficiency and possibility of extension. It can be used for not only alternative communication, in which communication line is not sufficient, but also for communication between home appliances. Korea Electronic Power Cooperation (KEPCO) is constructing the system, which automatically collects values of power consumption of every household. Due to the randomness and complicated physical characteristics of PLC protocol (KS X4600-1), it has been believed that the current PLC is secure in the sense that it is hard that an attacker guesses or modifies the value of power consumption. However, we show that the randomness of the protocol is closely related to state of the communication line and thus anyone can easily guess the randomness by checking the state of the communication line. In order to analyze the security of PLC, we study the protocol in detail and show some vulnerability. In addition, we suggest that PLC needs more secure protocol on higher layers. We expect that the study of PLC help in designing more secure protocol as well.

• Journal of the Korean Institute of Gas
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• v.4 no.4 s.12
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• pp.20-24
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• 2000

The electrostatic safety consciousness of safety manager were investigated through questionnaires sent to liquid petroleum gas stations in Korea. In addition, hazards of fire and explosion due to electrostatic on synthetic-polymer-wears and cotton-wears were estimated experimentally. The results of questionnaires indicate most workers wear their working clothes indiscreetly owing to lack of knowledge of preventing electrostatic hazards. The amounts of electrostatic charge generated in synthetic-polymer-wears were 1.79, 1.44 and 1.02 $\mu$C in winter, spring and autumn and summer, respectively. All these values exceed the limit of working wears of 0.60$\mu$C requested by Korea Standard(KS K-7807) for preventing electrostatic hazards, which means hazards may occur. While, the charge in cotton-wears were in the range of 0.42 to 0.52$\mu$C, which suggests that the cotton-wears investigated in this study have no problem of hazards. Therefore workers, visual and experiential education are necessary for elevating the standard of on electrostatics. It is also necessary to establish standards of wearing for preventing electrostatic hazards.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.11
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• pp.1530-1541
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• 2007

The purpose of this study is to establish a standard sizing system for Taekwondo uniforms. The sample utilized in the study consisted of 5,679 male and female subjects, obtained from Size Korea Project. Twenty three measurements were identified and selected as critical in the design and construction of Taekwondo uniforms. The results were as follows: First, it was determined that all brands used "height" as a key dimension of size designation. Two of brands added "chest girth" or "numeric numbers" to designate size in addition to "height". For example: 1) height/chest girth, 2) height/numeric number. The size pitches of all current Taekwondo uniforms in the market were 10cm of height for all brands. Second, the study showed male measurements were larger and longer than females, establishing that independent sizing specifications by sexes are needed. Third, in case of Taekwondo shirts, height and chest girth were selected as control dimensions. In case of pants, height and waist girth were selected as control dimensions. For selecting optimal sizing pitch, 2 different pitches of chest girth and waist girth(4cm pitch by KS and 8cm pitch by researchers) were compared, while height pitch was fixed at 10cm. Fourth, based on the analysis of the measurements(coverages and coverage efficiency rates), it was determined that 8cm pitches of chest and waist girth were efficient in both upper and lower Taekwondo uniforms. Fifth, subjects distribution counts and percentages were shown after analyzing coverage efficiency rates. Separate results are noted for the upper and lower Taekwondo uniforms. As previously mentioned, height pitches were 10cm and chest and waist pitches were 8cm. Finally, as a result of this research, key and referable measurements relevant to making Taekwondo uniforms were identified for male and female uniform. In case of Taekwondo shirts, 18 sizes were established for men, 16 sizes for women. Twenty five sizes for men and 20 sizes for women were presented in size tables for pants.

• Journal of Distribution Science
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• v.13 no.7
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• pp.41-51
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• 2015

Purpose - This study analyzes loading efficiency by loading pattern for package standardization and reduction of logistics costs, along with the creation of revenue for the revenue review panel (RRP) of Membership Wholesale Clubs (MWC). The study aims to identify standard dimensions that can help improve the compatibility of the pallets related to display patterns preferred by the MWC and thereby explore ways to enhance logistics efficiency between manufacturers and retailers through standardization. Research design, data, and methodology - The study investigates and analyzes the current status based on actual case examples, i.e., manufacturer A and Korea's MWC (A company, B company, and C company), and thus devises improvement measures. To achieve this, the case of manufacturer A delivering to MWC was examined, and the actual pallet display patterns for each MWC were investigated by visiting each distribution site. In this study, TOPS (Total Optimization Packaging Software, USA) was used as the tool for pallet loading efficiency simulations the maximum allowable dimension was set to 0.0mm to prevent the pallet from falling outside the parameters, and the loading efficiency was analyzed with the pallet area. In other words, the study focused on dimensions (length x width x height) according to the research purpose and thereby deduced results. Results - The analysis of pallet loading patterns showed that the most preferred loading patterns for loading efficiency according to product specification, such as pinwheel, brick, and block patterns, were used in the case of the general distribution products, but the products were configured with block patterns in most cases when delivered to MWCs. The loading efficiency by loading pattern was analyzed with respect to 104 nationally listed standard dimensions. Meanwhile, No.51 (330 × 220mm) of KS T 1002 (1,100 × 1,100mm) was found to be the dimension that could bring about an improved loading efficiency, over 90.0% simultaneously in both the T-11 and T-12 pallet systems in a loading pattern configuration with the block pattern only, and the loading efficiency simulation results also confirmed this as the standard dimension that can be commonly applied to both the T-11 pallet (90.0%) and the T-12 pallet (90.7%) systems. Conclusions - The loading efficiency simulation results by loading pattern were analyzed: For the T-11 pallet system, 17 standard dimension sizes displayed the loading efficiency of 90.0% or more as block patterns, and the loading capacity was an average of 99.0%. For the T-12 pallet system, 35 standard dimension sizes displayed the loading efficiency of more than 90% as block patterns (the average loading efficiency of 98.6%). Accordingly, this study proposes that the standard dimensions of 17 sizes with the average loading efficiency of 99.0% should be applied in the use of the T-11 pallet system, and those of 35 sizes with the average loading efficiency of 98.6% should be reviewed and applied in the use of the T-12 pallet system.

• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.302-311
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• 2022

Sound barrier walls are one of the most effective alternatives for reducing environmental noise on roads and railways in the city center. The insertion loss of the sound barrier against road traffic noise is the sum of the sound transmission loss, sound absorption loss, and sound energy reduction due to the diffraction attenuation of the sound barrier. The sound transmission loss of the sound barrier is one of the important factors that determine the insertion loss of the sound barrier and is a basic indicator that determines the performance of the sound barrier. Nevertheless, there is not a separate standard in Korea for measuring the acoustic transmission loss of sound barrier panels. There are only a few conditions in KS F 4770 series that stipulates on the general material of sound barrier panels. This thesis examines the necessity of the acoustic transmission loss measurement and evaluation standards of sound barrier walls, and seeks a measurement method in a free sound field (anechoic chamber) sound receiving room considering the characteristics of sound barrier walls installed in external spaces, unlike indoor building materials. In addition, a single number evaluation method using a reference spectrum was proposed so that the sound insulation effect according to various installation places such as roadside or railroad side can be easily displayed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.6
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• pp.258-263
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• 2008

The fine aggregates of below 2 mm size was fabricated using by the vertical furnace in which the aggregates could be sintered at floating state and its physical properties were analyzed. The liquid formed at the surface of specimens sintered at $1200{\sim}l300^{\circ}C$ induced a gas in core to expand so the denser shell and porous core could be produced. The C series specimen fabricated by crushing an extruded body had an irregular shape and sharp edges but those became spheroidized by bloating due to gas expansion inside. The fine aggregates fabricated in this study was as light as floating in the water and had an apparent density of $0.68{\sim}1.08$. The absorption rate was proportioned to a porosity showing that the pores in core was not closed completely. The properties of fine aggregates fabricated in vertical furnace were similar with those of in an electric muffle furnace but the sticking-together phenomenon by surface fusion was not occurred in the vertical furnace. The aggregates fabricated in this study had a little lower impact resistance than that of natural aggregate but satisfied the unit volume weight standard specified in KS.

• Fire Science and Engineering
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• v.25 no.4
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• pp.35-41
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• 2011

Casualties due to toxic smoke products have been reported as major fire damage. There are various tests in order to evaluate toxic smoke from a fire at home and abroad, and KS F 2271 as a test of the gas hazard of building finish materials has been conducted in Korea. The current test of the gas hazard exposes rodent, laboratory rat, to smoke gases to evaluate combustion gas toxicity by measuring acting time of that. this study performed a test of the gas hazard for combustible polymer material, Urethane and rubber flooring, and determined gases with the FT-IR. Quantitative results compared with standard value defined in BS6853 and toxicity index (R) was calculated. Using relative comparison with animal test and the toxicity index, We tried a variety of toxicity evaluation by correlation analysis of two tests.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.34-45
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• 2009

In domestic, the Quality Management system of construction work has been compounded of the association of regulation which is ground for relevant law and operation of Quality Management system by ISO/KS A 9001(QMS) established by the contractor. Two quality guaranteed systems must be operated with complementary and integrated system, but we can not make full use of QMS of contractor and only run routinized quality management system in all construction project by the standard, methods, process provided in the law. These problems were demanded better condition in the past ten years, since the ISO standards have been introduced. Establishing preventive consideration of quality management by setting a goal of drastic quality guarantee is an urgent problem of construction industry. This study is quick to fellow, which should do three things. 1. The attitude survey related quality management of staff in charge in construction site has run. 2. Base on these results, we adjust satisfaction measurement about operation of construction quality management system. 3. Subsequently, we want to offer our thesis about advanced opinion for the next.

• Journal of the Korean Chemical Society
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• v.42 no.4
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• pp.383-390
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• 1998

The interaction of phenoxide anion with several cationic surfactant micelles (DTAB, TTAB, CTAB, CDEAB, and CTAC) was studied by UV/Vis spectrophotometric method. The solubilization constants of phenoxide anion into the cationic micellar phase and the critical micelle concentration of these surfactants in the presence of the phenoxide anion could be determined from the absorbance changes. The measured solubilization constants were changed according to the following order: $K_s(CTAC)>K_s(CDEAB)>K_s(CTAB)>K_s(TTAB)>K_s(DTAB).$ Effects of salts(NaCl and NaBr) and n-alcohols(butanol, pentanol, and hexanol) on the solubilization of phenoxide anion by the TTAB system have been also measured and analyzed. There was a great decrease of solubilization constant and CMC with these additives. The standard Gibbs free energy, enthalpy, and entropy changes for the solubilization of phenoxide anion by the TTAB system were calculated from the temperature dependence of $K_s$ values.

• Korean Journal of Construction Engineering and Management
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• v.14 no.3
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• pp.33-41
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• 2013

This study used TRIZ methodology to develop a new steel stud for load bearing or non-load bearing walls. Technical contradiction of high strength with high insulation performance can be solved by TRIZ. We suppose a new shape of high-strength insulated (HSI) Stud. This study showed TRIZ can be usefully applied to the development of new construction materials by solving technical contradictions. Insulation performance of HSI stud can be improved approximately 12% compared to the standard KS stud. Although up to 3.9% of the flexural strength degradation is expected, compressive strength of HSI studs are improved from 4.1% to 8%. In conclusion, improved thermal performance and higher strength can be expected for the HSI stud developed using TRIZ.