• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.9
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• pp.598-605
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• 2014

In this paper, we suggest a modified slotted ALOHA algorithm for fast tag collection in active RFID system and implement the reader and tag operation using CC2530 chip of Texas Instruments Co. to prove the performance of the proposed algorithm. In the present international standard related with active RFID including ISO/IEC 18000-7 the reader sends sleep command to each tag after successful obtaining tag's information. Meanwhile, in this paper, the tags decide to sleep after checking the second command from the reader resulting in enormously decreased tag collection time. We tested the proposed algorithm with 30 tags over the range of 0-3m and the results showed that the tag collection process was completed in 400msec at average. And 30 tags are collected in one second with 99.7% and the collection rate is 100% in 2m distance between reader and tag. The collection rates are 99.94% and 99.7% for distance 2.5m and 3m, respectively. The average collection rate is 99.91% over all range and it is concluded that the proposed algorithm is enough to apply to real fields.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.2A
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• pp.177-183
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• 2009

In this paper, we propose an improved anti-collision algorithm. We have designed an anti-collision unit using this algorithm for the 18000-6 Type C Class 1 Generation 2 standard (Gen2). The Gen2 standard uses a Q-algorithm for incremental method on the Dynamic Slot-Aloha algorithm. It has basically enhanced performance over the Slot-Aloha algorithm. Unfortunately, there are several non-clarified parts: initial $Q_{fp}$ value, weighted C, and the ending point of the algorithm. If an incorrect value is selected, it causes degradation in performance. Thus we propose an improved anti-collision algorithm by clearly defining the vague parts of the existing algorithm. Simulation results showed an improved performance of up to 34.8% using an optimized value of C and the initial $Q_{fp}$ value. With the ending condition, performance is 34.7%. The anti-collision unit is designed using the Verilog HDL. The module was synthesized using Synopsys' Design Compiler and the TSMC $0.2{\mu}m$ standard cell library. The synthesized result yielded 3,847 gates, and was guaranteed under the proposed working frequency of 19.2MHz.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.407-417
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• 2024

The objective of this study is to predict and reduce potential damage caused by chlorine gas leaks, a hazardous material, when vehicles transporting it overturn due to accidents or other incidents. The goal is to forecast the anticipated damages caused by chlorine toxicity levels (ppm) and to design effective response strategies for mitigating them. To predict potential damages, we conducted quantitative assessments using the ALOHA program to calculate the toxic effects (ppm) and damage distances resulting from chlorine leaks, taking into account potential negligence of drivers during transportation. The extent of damage from toxic gas leaks is influenced by various factors, including the amount of the leaked hazardous material and the meteorological conditions at the time of the leak. Therefore, a comprehensive analysis of damage distances was conducted by examining various scenarios that involved variations in the amount of leakage and weather conditions. Under intermediate conditions (leakage quantity: 5 tons, wind speed: 3 m/s, atmospheric stability: D), the estimated distance for exceeding the AEGL-2 level of 2 ppm was calculated to be 9 km. This concentration poses a high risk of respiratory disturbance and potential human casualties, comparable to the toxicity of hydrogen chloride. In particular, leaks in urban areas can lead to significant loss of life. In the event of a leakage incident, we proposed a plan to minimize damage by implementing appropriate response strategies based on the location and amount of the leak when an accident occurs.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.419-427
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• 2024

This study assessed the potential impact of gas leakage resulting from accidental damage to buried urban gas pipelines during perforating operation near subway construction sites. The risk of explosions due to ignition sources such as static electricity, arising from gas infiltrating the subway construction site through storm sewers and sewage pipes, was evaluated using the ALOHA program. The results of the threat zone calculation, which input various parameters of urban gas pipelines such as length, diameter, and pressure, indicated that the flammable area within the vapor cloud extended from 1.2 to 1.4 km (red zone), the blast area ranged from 0.8 to 1.0 km (yellow zone), and the jet fire extended from 45 to 61 m (red zone). This study demonstrates that within the flammable area of the vapor cloud, a specific combination of concentration and conditions can increase flammability. The blast area may experience explosions with a pressure of 1.0 psi, sufficient to break glass windows. In the event of a jet fire, high temperatures and intense radiant heat exposure lead to rapid fire propagation in densely populated areas, posing a high risk of casualties. The findings are presented in terms of the sphere of influence and threat zone ranges.

• The Transactions of the Korea Information Processing Society
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• v.5 no.4
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• pp.1057-1065
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• 1998

This paper describes a new fractal image coding algorithm to shorten time to take on fractal image encoding by using limited search area method and scaling method. First, the original image is contracted respectively by half and by quarter with the scaling method. And then, the corresponding domain block of the quarter-sized image which is most similar with one range block of the half-sized image is searched within the limited area in order to reduce the encoding time extremely. This searched block is used in encoding. Also, we propose an algorithm provided much shorter encoding time and better compression ratio with a little degradation of the decoded image quality than Jacquin's method.

• Fashion & Textile Research Journal
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• v.19 no.6
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• pp.777-785
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• 2017

The MICE industry is a new industry that combines corporate meetings, intensive tours, conventions and exhibitions. The convention (the international conference itself) is a conception born from the interpretation of multiple industries such as conferences, incentive tourism, exhibitions and fairs. It is therefore necessary to develop products that can contribute to the revitalization of the MICE industry. We will participate in globalization era trends by developing original design with unique color sense as well as traditional beauty and elegance that can represent the Korean Wave in order to develop high value-added fashion cultural products. We examine the formative characteristics of Chogakbo and apply them to the harmony of geometrical characteristics and colors. The morphological characteristics and sewing method of the Korean traditional 'fo' were also used for shirt designs. It is a fashion cultural product that applies to the Korean Cheokagbo design as well as maintains a basic aloha shirt design that can be worn by everyone (regardless of gender and age) to make it globally acceptable. We used a simple and interesting geometric configuration of the surface represented by the surface composition of the patchwork as well as proposed a design costume by 3D clothing simulation work. The research results can be used as basic data for the domestic fashion market and cultural goods market.

• Elastomers and Composites
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• v.46 no.2
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• pp.158-163
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• 2011

Rigid polyurethane foam (PUF) was synthesized with different contents of aliphatic polyester polyol, aromatic polyester polyol and aliphatic polyether polyol to know change of properties under sea water. UTM(universal testing machine), DSC(differential scanning calorimetry), hardness meter and FT-IR(Fourier transform spectroscopy) were used to study the PUF`s physical properties under sea water. Compressive strength and hardness of PUF decreased with increasing the content of aromatic polyester polyol under sea water as aging. According to the results of IR spectral analysis, reduction of urethane and urea peak was found and allophanate and biuret peak increased. Although glass transition temperature of PUF increased, mechanical properties of PUF decreased under sea water, because PUF gets brittle when crosslink density increase.

• Fashion & Textile Research Journal
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• v.10 no.6
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• pp.857-863
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• 2008

The purpose of this study is to analyze the types of Hibiscus patterns expressed on Aloha shirts. This study analyzed real data collected from man's aloha shirts displayed at the International Market Place in Waikiki of Hawaii during January 21-27, 2007. 35 pieces of Aloha shirts with Hibiscus Patterns were was analyzed. The total of each analysis means all number of patterns sampled or appeared to analyze the types of patterns. The motif of Hibiscus was sampled a total of 42 units for some shirts having several motifs. Its motif was divided into two groups, 20 units(47.62%) of natural type and 22 units(52.38%) of stylized type, according to modeling. Two types were much the same percentage. Hibiscus patterns were classified into three groups, isolated, band and arabesque type, by formation type. The isolated type was appeared most frequently. The layout of Hibiscus pattern was classified into three groups, engineered print, all over print and border print. All over print was appeared most frequently. The data of this study will be provided as a resource to promote using and developing of the pattern of Korean rose of Sharon.

• Textile Coloration and Finishing
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• v.24 no.2
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• pp.145-151
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• 2012

Polymer alloys of poly(ethylene terephthalate)(PET) and nylon6(PA6) which were not miscible each other by themselves were successfully prepared through melt compounding using a twin-screw extruder by utilizing epoxy as reactive compatibilizer. At the epoxy(DGEBA) amount of 0.5~2wt%, the domain size(average diameter) of the discontinuous phase could be reduced up to 0.2${\mu}m$ from 1-5${\mu}m$ that of the simple blend without epoxy. The reaction was presumed to happen mostly at interphase from the result of maximum increase of melt viscosity at the middle range of PET/PA6 blend ratio. It is expected that alloy fibers of PET/epoxy/PA6 with enough mechanical strength for use can be prepared.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.757-767
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• 1996

Poly(alkyl acrylate-g-caprolactone) graft copolymers were prepared, and they were applied as compatibilizing agents for polycarbonate (PC) / poly(acrylonitrile-butadiene-styrene) (ABS) blends. The incompatible poly(alkyl acrylate) segment was incorporated into the graft copolymer in order to localize the copolymer at the PC/ABS interface. The blend containing 1 phr of the copolymer showed remarkable improvement in impact strength as well as in elongation at break. Impact improvement was more pronounced with a thinner test specimens of 1/8 inch thickness. Morphological study showed that the presence of the graft copolymer led to a smoother PC/ABS interface due to the interfacial enrichment of the graft copolymer.