• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1393-1401
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• 2013

What is RFID Microchip tag attached to an object, the reader recognizes technology collectively, through communication with the server to authenticate the object. A variety of RFID tags, 13.56Mhz bandwidth RFID card, ISO/IEC 14443 standards based on NXP's Mifare tag occupies 72.5% of the world market. Of the Mifare tags, low cost tag Mifare Classic tag provided in accordance with the limited hardware-based security operations, protocol leaked by a variety of attacks and key recovery vulnerability exists. Therefore, in this paper, Cryptography Scheme and Secure Protocol for Safety Secure Scheme Construction in 13.56Mhz RFID have been designed. The proposed security scheme that KS generated by various fixed values and non-fixed value, S-Box operated, values crossed between LFSR and S-Box is fully satisfied spoofing, replay attacks, such as vulnerability of existing security and general RFID secure requirement. Also, It is designed by considering the limited hardware computational capabilities and existing security schemes, so it could be suit to Mifare Classic now.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.2
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• pp.49-59
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• 2016

According to KS and Standard Specifications for Concrete, the compressive strength of concrete containing recycled aggregate is limited to 27 MPa and thereafter there are little research on concrete containing recycled aggregate of its compressive strength of greater than 27 MPa. Therefore, to expand the applicability of concrete recycled coarse aggregate(RCA), this paper concerns the mechanical properties of concrete containing RCA with compressive strength ranging from 30 to 60 MPa. The experimental parameters were water-cement ratio and replacement ratio of RCA. Water-cement ratio(w/c) was 0.36, 0.46 and 0.53, and replacement ratio of RCA was 30, 50, 70 and 100%. The experimental results were discussed about compressive strength, elastic modulus, split tensile strength and modulus of rupture. Test results of elastic modulus were compared to the design code predictions. Experimental elastic modulus for concrete with w/c=0.53 decreased by greater than 10% compared with that for concrete with w/c=0.36. The design code predictions for elastic modulus overestimated the experimental results. Whereas, the design code predictions for modulus of rupture underestimated the measured values.

• Journal of the Korean GEO-environmental Society
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• v.24 no.3
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• pp.5-14
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• 2023

The dry unit weight of the soil can be obtained by measuring the weight of the oven dried soil. According to the Korean Industrial Standards (KS F), oven dried soil at 110±5℃ continuously increases in weight when exposed to air. However, there is no regulation on the weight measurement time of oven dried soil, making it difficult to accurately measure the dry weight. In this study, a method to easily determine the dry weight was presented through the analysis of the weight singularity that appears during weight measurement. The weight singularity represents the smallest value among the measured weights, and is the weight at which the effect of moisture absorption in the air of the sample is minimized. In the course of the experiment, a container was selected using a statistical analysis method, and a photograph of the soil samples were presented using an optical microscope. In addition, the temperature of the weight singularity was measured using a non-contact infrared thermometer. As a result of analyzing the weight singularity of six types of soil, including Jumunjin sand, Naeseong stream sand, Yecheon weathered granite soil, Jeju sand, Sabkha sand, and Ulleung sand, the weight singularity of oven dried sample appeared between 8 and 27 seconds after weight measurement, and the temperature ranged from 103.4 to 108.13℃. The weight decrease rate of the singularity was 0.0066 to 0.0085% depending on the soil samples.

• Journal of the Korean GEO-environmental Society
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• v.24 no.9
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• pp.25-32
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• 2023

The Korean Industrial Standards (KS F) have a various regulations for measuring the weight of dried soil and rock. However, if the dried weight is measured in air after drying at 110±5℃ or 105±5℃, a weight singularity occurs, in which the weight decreases and then increases as the measurement time continues. In this study, basaltic rock from Ulleung Island was oven dried at 40 to 110℃. The weight was measured on an electronic scale with a sensitivity of 0.0001g (0.1mg) to find weight singularities. A method to easily determine the dry weight using the weight singularities was presented. As a result of analyses of the singularity of rock specimen according to temperature, the singularities were appeared in the temperature range of 40 to 110℃, and the weight of the singularity was smaller as the heating temperature increased. In particular, the weight singularity duration appeared, and the duration of the singularity was shorter as the heating temperature increased. The results of the convection measurement experiment showed that the cause of the singularity is the convection phenomenon caused by the contact of the heated rock with the air. The weight decrease of oven dried rock occurs when the effect of convection is dominant over the effect of air moisture absorption. Conversely, the weight increase of rock occurs when the effect of air moisture absorption is dominant over the effect of convection.

• Magazine of the Korean Society of Agricultural Engineers
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• v.21 no.4
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• pp.99-107
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• 1979

In order to investigate the utilization of industrial waste and briquette ash for concrete production, briquette ash was used as fine aggregate for mortar production and three different kinds mortars were produced by mixing carbide and bottom aches with cement. These products were compared with mortar, produced by standard sand, in the respects of compressive, tensil and bending strengths. Further study on the economic aspect of utilization of briquette ash is needed but the results obtained from our preliminary study are summarized as follows : 1. The compressive strengths at the age of seven days of mortars, made of one to two ratios of cement to briquette ash, (cement+carbide ash) to briquette ash and(cement+bottom ash) to briquette ash were 70%, 61% and 58%, respectively, of the mortar made of standard sand. The compressive strengths of those mortars at the age of 28 days were 56%, 49% and 48% of the mortar made standard sand. 2. The compressive strengths at the age of seven days of the mortar made of one to two ratios of cement to briquette ash, (cement+carbide ash) to briquette ash and (cement+bottom ash) to briquette ash were 84%, 73%, and 70% of the mortar which was produced according to Korean Standard Value. The compressive strengths of those mortars at the age of 28 days were 85%, 73% and 73% of the mortar of the Korean Standard value. 3. The tensil strengths at the age of seven days of the mortars made of one to two ratios of cement to briquette ash, (cement+carbide ash) to briquette ash, and (cement+bottom ash) to briquette ash were 64%, 36%, and 36%, respectively, of the mortar of standard sand. The tensil strengths of those mortars at the age of 28 days were 70%, 47%, and 39%, respectively, of the standard mortar. The mortars made of one to two ratios of cement to briquette ash at the age of seven and 28 days were higher than the mortars of Korean Standard. The other mortars were 61 to 62% at the age of seven days and 75 to 90% at the age of 28 days of the Korean Standard mortar, respectively. 4. The bending strengths at the age of seven days of mortar made of one to two ratios of cement to briquette ash, (cement+carbide ash) to briquette ash, and (cement+bottom ash) to briquette ash were 46%, 53% and 50% of the mortar of standard sand. The bending strengths of those mortars at the age of 28 days were 90%, 77% and 69%, respectively of the mortar of standard sand. 5. The mortar of briquette ash which was lower in strengths compared with the mortar of cement have shown possibility of its secondary products of cement and concrete. The uses of briquette ash and industrial waste as construction materials would contribute toward solving various pollution problems caused by industrial wastes and saving labor costs needed to cleaning up. Furthermore, the effective use of briquette ash would greatly save the aggregate resources.

• Journal of the Korean Geotechnical Society
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• v.31 no.1
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• pp.53-64
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• 2015

This study presents the experimental results of pervious blocks subjected to a series of unique inflow conditions in urban area. The measured properties include the strength, permeability, drainage capacity and runoff, and evaporation for blocks made of two different size of aggregates. Results revealed that the strength satisfies the Korean Standard regardless of aggregate size whereas the immediate runoff occurred for the block with small size aggregate. On the other hand, the block with large aggregates allowed the drainage upon the initial inflow condition, which became hampered to induce the runoff by subsequent inflow. It was attributed to the fact that the capillary water often served as the hydraulic barrier in partially saturated condition. The salient observation indicated that the runoff highly depended on the evaporation and pre-wetting condition as well as the porosity and pore connectivity. The bilinear evaporate rate that makes the degree of saturation vary also had great influence on deterining the time-dependent runoff.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.4 s.334
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• pp.29-36
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• 2005

This paper presents the first hardware design of ARIA that KSA(Korea Standards Association) decided as the block encryption standard at Dec. 2004. The ARIA cryptographic algorithm has an efficient involution SPN (Substitution Permutation Network) and is immune to known attacks. The proposed ARIA design based on 1 cycle/round include a dual port ROM to reduce a size of circuit md a high speed round key generator with barrel rotator. ARIA design proposed is implemented with Xilinx VirtexE-1600 FPGA. Throughput is 437 Mbps using 1,491 slices and 16 RAM blocks. To demonstrate the ARIA system operation, we developed a security system cyphering video data of communication though Internet. ARIA addresses applications with high-throughput like data storage and internet security protocol (IPSec and TLS) as well as IC cards.

• Fire Science and Engineering
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• v.29 no.4
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• pp.1-6
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• 2015

It is necessary to obtain a fire resistance certification in order to use SFRM in Korea. The fire resistance tests for certifications are performed separately for beams and columns and the certifications are different. We could assume that the same SFRM has different thicknesses for beams and columns because the conditions of the fire resistance tests for them differ in the section factors etc. But most of the SFRMs in Korea have the same thicknesses for beams and columns. So the question arises as to there were the differences between the fire test results for beams and columns reside. The purpose of this study is to consider the separate evaluation of the fire resistance of members through a comparative analysis of the temperature data obtained from fire certification tests.

• Journal of Korean Society of Steel Construction
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• v.24 no.4
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• pp.435-442
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• 2012

Recently, high performance(strength) steels have been utilized to structural materials in buildings and bridges with the demand for high-rise and long-span of main structures. This paper is a series of basic study for the design specification of structural members using high performance steel, material properties of high performance rolled steel building structures. HSA800 was compared with the requirements of Korean Standards(KS) for HSA800. Welded square tube stub columns with variables of width-to-thickness ratios are planned in order to investigate the local buckling behaviors and check the current design limit of width-to-thickness ratio and uniaxial compressive tests are carried out. In addition, the local buckling behaviors of stub columns obtained finite element analysis were compared with those of test results.

• Journal of Korean Society for Quality Management
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• v.31 no.3
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• pp.62-84
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• 2003

The typical reason of the private sector's increasing share in standardization is that the procedures of official standardization organizations are out of step with the rate of technical development. At today's so fast pace that the success of a technology is decided in the market even before it is standardized, several industry leaders jointly make their draft standard at the early stage of development, which becomes 'De fecto Standard.' To respond effectively to current trends of standardization where the market's decision is thought much of than official standardization procedures, it is necessary to shift from our current public sector-driven to private sector-driven standardization. Therefore, to vitalize the private sector-driven standardization in Korea, there is a need to: Run a standard foundation to secure stable resources for standardization Make information exchange between the govertment and private sector active and policy-making on standards consistent by designating a private organization to cover the roles, policies on standards, and support of the national standardization organization Establish a system to make private sector-driven standards approved as international standards Offer a training program to forster standard experts Publicize the importance of standards Promote standardization forums driven by private businesses, like the Integrated Forum. Maximize the benefits of linking standards and patents Now, Korea is on the threshold of developing into a world-class standard leader, and the private sector-driven standardization should be a stepping-stone for crossing over the threshold. This study is designed to suggest a method of promoting private sector-driven standardization to effectively cope with fast-changing international standards, based on the cases in developed countries.