• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.1009-1018
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• 2017

We developed new Digital Sampler for KVN(: Korean VLBI Network). The sampler has 1024MHz sampling frequency with 2bits/sample. The sampler's input reference frequencies are 1pps(: pulse per second) and 10MHz, also UTC(: Universal Time Coordinated) time information out with 1PPS signal, synchronized. The output of sampling data is adapted VSI(: VLBI Standard Interface) specification including the time information. In order to confirm the performance of the sampler, we carried out the astronomical radio observation test in Ulsan Radio Observatory of KVN. It was confirmed the stable performance. In this paper, We introduce the new developed sampler and present the observational test result.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.37-47
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• 2004

The security of personal informations has been an important issue since the field of smart card applications has been expanded explosively. The security of smart card is based on cryptographic algorithms, which are highly required to be implemented into hardware for higher speed and stronger security. In this paper, a SEED cryptographic processor is designed by employing one round key generation block which generates 16 round keys without key registers and one round function block which is used iteratively. Both the round key generation block and the F function are using only one G function block with one 5${\times}$l MUX sequentially instead of 5 G function blocks. The proposed SEED processor has been implemented such that each round operation is divided into seven sub-rounds and each sub-round is executed per clock. Functional simulation of the proposed cryptographic processor has been executed using the test vectors which are offered by Korea Information Security Agency. In addition, we have evaluated the proposed SEED processor by executing VHDL synthesis and FPGA board test. The die area of the proposed SEED processor decreases up to approximately 40% compared with the conventional processor.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.324-333
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• 2016

Objectives: We aimed to compare the sampling performance of different flow-based impactor samplers for collecting fungal spores and bacteria and to explore the association of the level of bioaerosols with activity patterns of occupants in daycare center settings. Methods: For comparison of sampling performance, two different flow-based samplers (greater than 100 L/min or not) were selected; a low flow-based sampler (one-stage Andersen sampler) and two high flow-based samplers (DUO SAS SUPER 360 sampler, BUCK bio-culture sampler). We collected airborne mold and bacteria in 30 daycare centers with various levels of contaminated air. Three repeat samplings per each sampler were performed. Mold and bacteria were grown for 96 hours at $25{\pm}1^{\circ}C$ and 48 hours at $35{\pm}1^{\circ}C$, respectively. The Andersen and SAS samplers were used for investigating the association between the level of bioaerosols and the activity patterns of occupants in daycares. Particular matters 10($PM_{10}$), temperature, and relative humidity were monitored as well. Samplings were carried out with one-hour interval from 9 to 5 O'clock. For statistical comparisons, Kruskal-Wallis test, Wilcoxon's signed rank test, and multiple regression analysis were carried out. Results: The airborne level of molds by the low flow-based sampler were significantly higher than that of high flow-based samplers (indoor, P=0.037; outdoor, P=0.041). However, no statistical difference was observed in the airborne level of bacteria by each sampler. Also the level of bioaerosols varied by the time, particularly with different activity patterns in daycare centers. The higher level of mold and bacteria were observed in play time in indoor. Similarly, the concentrations of $PM_{10}$ were significantly associated with the level of bioaerosols (P<0.05). Conclusions: Our findings indicate that the flow rate of sampler, rather than total air volume, could be able to affect the results of sampling. Also, the level of airborne mold and bacteria vary behavior patterns of occupants in indoor of daycare settings. Therefore, different samplers with other flow rate may be selected for mold or bacteria sampling, and activity patterns should be considered for bioaerosol sampling as well.