• Journal of KIISE:Computing Practices and Letters
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• v.14 no.3
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• pp.251-255
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• 2008

In most file systems, if a file is deleted, only the metadata of the file is deleted or modified and the file's data is still stored on the physical media. Some users require that deleted files no longer be accessible. This requirement is more important in embedded systems that employ flash memory as a storage medium. In this paper, we propose a secure deletion method for NAND flash file system and apply the method to YAFFS. Our method uses encryption to delete files and forces all keys of a specific file to be stored in the same block. Therefore, only one erase operation is required to securely delete a file. Our simulation results show that the amortized number of block erases is smaller than the simple encryption method. Even though we apply our method only to the YAFFS, our method can be easily applied to other NAND flash file systems.

• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.48-58
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• 2002

As a pilot experiment for developing the monitoring system for oil spill from storage tank, previous approach of monitoring contaminated oil from mixed soil sample had the limitation that it cannot reflect the real situations of the contamination. In this study, more realistic contamination condition and water contents were considered. Fluorescence intensity was not affected by water contents. To acquire the stability of media, sand, Ca-bentonite, alumina, Fe-oxide, bead and silica were tested. Only sand was suitable to our system. These results should provide basic information for constructing reliable monitoring system.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2009.04a
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• pp.295-303
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• 2009

The annals of Joseon dynasty, especially the volumes of King SeJong(1418-1450 A.D.), were heavily deteriorated by fungi. Investigations on the deteriorating and foxing fungi were carried out. Fungal structures on the beeswax, which were coated on the both side of Han-Ji, were suspected to be involved in the deterioration, and were observed by SEM. Isolation and culturing of these fungi were tried by scrubing swab samples and placing on the artificial media. Culture-independent approaches were used to identify the fungal strains associated with damages of beeswax and foxing of the paper by the analyses based on DNA sequences data from the specific ITS region of rDNA regions. In addition, well-known paper staining fungi(PSF), i.e., Aspergillus terreus var. terreus, Fusarium oxysporum, Chaetomium globosum, Cladosporium cladosporioides, and Alternaria solani, were compared in the mycelial growth and stain on beeswax and papers under different environmental conditions (temperature, light, moisture, etc). Fungal strains isolated from the air samples in the storage room and shelves were identified as Irpex sp., Arthrinium sacchari, Cladosporium tenuissimum, Aspergillus sclerotiorum, Sistotrema brinkmannii, and Hypoxylon bovei var. microsporum The isolated strains were compared in growth and stain patterns on beeswax and papers(Han-Ji, Hwa-Ji, and Yang-Ji) whether these can cause damage or foxing on the annals or not.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.14 no.2
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• pp.178-181
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• 2014

Hunter syndrome (mucopolysaccharidosis type II, MPS II) is a X-linked lysosomal storage disease caused by a deficiency in the lysosomal enzyme, iduronate-2-sulfatase (IDS), leading to accumulation of glycosaminoglycans within lysosomes of many organs and tissues. Since the enzyme replacement therapy was approved and available in the treatment of MPS I, II, VI, early diagnosis and early therapy can bring the better prognosis of disease and the better quality of life in patients. We described a 2.5 year old child presented with frequent otitis media and developmental delay including speech impairment, who was diagnosed as Hunter syndrome with IDS NM_000202.5:c. 263G>A(p.Arg88His) mutation.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.596-598
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• 2009

현재 상용화되어 있는 petri dish는 미생물 배지의 보관기간이 $4^{\circ}C$의 온도에서 15~50일 정도 되기 때문에 장기저장이 어렵다. 그래서 본 연구는 자체 고안된 LOP(Lab on a plate)와 petri dish에 고체배지를 제조하여 배지의 수분함량을 비교하기 위한 연구를 수행하였다. 본 연구에 사용한 배지는 Bacillus cereus 배양을 위한 MYP(Mannitol Egg Yolk Polymyxin) agar로 이용하여 제조하였으며 각각 진공포장 및 비포장하여 $4^{\circ}C$와 $25^{\circ}C$의 온도조건에서 6주 동안 매주 수분함량을 측정한 결과, LOP와 petri dish 모두 비포장 조건보다 진공포장조건의 수분보호능이 우수 하였으며 진공포장조건에서는 $25^{\circ}C$가 $4^{\circ}C$보다 상대적 수분 보호능이 좋음을 확인할 수 있었다. 또한, 비포장조건에서도 LOP가 $4^{\circ}C$와 $25^{\circ}C$ 모두 petri dish보다 수분보호능이 탁월하여 유통기간이 훨씬 더 연장될 수 있는 가능성을 보여 주어 앞으로 LOP를 이용한 장기 보관과 즉시 사용이 가능한 pre-plated media와 관련된 다양한 제품의 용기로 사용 가능할 것으로 기대된다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.569-577
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• 1996

This experiment was conducted to investigate the effects of water potential by PEG treatment on germination and quantitative changes of seed storage reserves of soybean [Glycine max (L.) Merr.], peanut(Arachjs hypogaea L.) and corn(Zea may L.). Water potential of PEG(M.W. 10, 000) solution as germination media was 0.0, -0.2, and -0.5MPa. The highest moisture uptake rate was found in soybean seedlings among three crops. Moisture content of seedlings of three crops was decreased at -0.5MPa treatment and seedling length was delayed with water potential decrement. As water potential decreased, decreasing rate of protein content of the seedlings compared to seeds was declined in soybean and peanut. Decreasing rate of starch content of the seedlings was decreased in corn at -0.5MPa treatment. Increasing rate of sugar content of the seedlings was markedly decreased at -0.5MPa treatment in all crops. The results of this experiment showed that availability of moisture and synthesis of sugar for seed germination were influenced below -0.5MPa water potential in three crops.

• Journal of Animal Science and Technology
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• v.46 no.6
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• pp.999-1006
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• 2004

The selective media including NPC agar, DHL agar, MacConkey agar, and Cetrimide desoxycholate agar were compared to determine selectivity for the growth of bacteria Cetrimide desoxycholate agar was better than NPC agar, DHL agar, and MacConkey agar for the growth of psychrotrophic grarn-negatve bacteria including Pseudomonas. and for the inhibition of gram positive bacteria The specificity of resazurin reduction time test was investigated to determine post-pasteurization contamination of market milk. Equal volume of Cetrimide desoxycholate broth was added to market milk, which was then incubated at $21^{\circ}C$ for 18 hours. The growth of bacteria in the incubated milk was detected in resazurin reduction time test. The results in resazurin reduction time test and total bacteria number count of market milk after storage at $7^{\circ}C$ were relatively correlated each other. Pseudomonas was isolated most frequently from the market milk stored at $7^{\circ}C$ for 10 days, and Acinetobacter and Aeromonas followed. Acinetobacter, Pseudomonas and Enterobacter were frequently isolated from the mixture of market milk and Cetrimide desoxycholate broth incubated at $21^{\circ}C$ for 18hours in resazurin reduction time test.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.127-132
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• 2006

Quantization in video coding plays an important role in controlling the bit-rate of compressed video bit-streams. It has been used as an important control means to adjust the amount of bit-streams to at]owed bandwidth of delivery networks and storage. Due to the dependent nature of video coding, dependent quantization has been proposed and applied for MPEG-2 video coding to better maintain the quality of reconstructed frame for given constraints of target bit-rate. Since Scalable Video Coding (SVC) being currently standardized exhibits highly dependent coding nature not only between frames but also lower and higher scalability layers where the dependent quantization can be effectively applied, in this paper, we propose a dependent quantization scheme for SVC and compare its performance in visual qualities and bit-rates with the current JSVM reference software for SVC. The proposed technique exploits the frame dependences within each GOP of SVC scalability layers to formulate dependent quantization. We utilize Lagrange optimization, which is widely accepted in R-D (rate-distortion) based optimization, and construct trellis graph to find the optimal cost path in the trellis by minimizing the R-D cost. The optimal cost path in the trellis graph is the optimal set of quantization parameters (QP) for frames within a GOP. In order to reduce the complexity, we employ pruning procedure using monotonicity property in the trellis optimization and cut the frame dependency into one GOP to decrease dependency depth. The optimal Lagrange multiplier that is used for SVC is equal to H.264/AVC which is also used in the mode prediction of the JSVM reference software. The experimental result shows that the dependent quantization outperforms the current JSVM reference software encoder which actually takes a linear increasing QP in temporal scalability layers. The superiority of the dependent quantization is achieved up to 1.25 dB increment in PSNR values and 20% bits saving for the enhancement layer of SVC.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.2
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• pp.134-142
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• 2012

This paper analyze an LDPC code replication method suitable for cloud computing. First, we determine the number of blocks suitable for cloud computing through analysis of the performance for the file availability and storage overhead. Also we determine the type of LDPC code appropriate for cloud computing through the performance for three types of LDPC codes. Finally we present the graph random generation method and the comparing method of each generated LDPC code's performance by the iterative decoding process. By the simulation, we confirmed the best graph's regularity is left-regular or least left-regular. Also, we confirmed the best graph's total number of edges are minimum value or near the minimum value.

• The Journal of Society for e-Business Studies
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• v.16 no.4
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• pp.1-16
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• 2011

A digital certificate mandated by the Electronic Signature Act has become familiar in our daily lives as 95% of the economically active population hold certificates. Due to upgrades to 256 bit level security that have become effective recently, the security and reliability of digital certificates are expected to increase. Digital certificates based on Public Key Infrastructure (PKI) have been known as "no big problem," but the possibility of password exposure in cases of leaked digital certificates still exists. To minimize this vulnerability, various existing studies have introduced alternative password methods, expansion of certificate storage media, and multiple certification methods. These methods perform enhanced functions but also have limitations including the fact that the secureness of passwords is not guaranteed. This study suggests an alternative method for enhancing the level of password secureness as a way to improve password security. This new method improves security management and enhances the convenience of using digital technologies. The results may be used for developing digital certificate related security technologies and research in the future.