| 1. |
- Jin, Young Hoon, et al.
(författare)
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Wavelet decomposition for detection of chaotic characteristics of monthly precipitation at Mokpo, Korea
- 2005
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Ingår i: 31st IAHR Congress 2005 : Water Engineering for the Future, Choices and Challenges - Water Engineering for the Future, Choices and Challenges. - 8987898245 - 9788987898247 ; , s. 429-437
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Konferensbidrag (refereegranskat)abstract
- In the present study, we apply deterministic chaos theory to investigate nonlinear dynamics in monthly precipitation at Mokpo, Korea, after wavelet decomposition. The wavelet transform is used not only for removal of noise but also for extraction of low and high frequency components in the data, representing low-dimensional dynamics. In order to determine an appropriate decomposition level for the wavelet transform, a correlation dimension analysis is applied for the respective low and high frequency signals after successive decomposition. The wavelet decomposition is performed up to 5th-level with orthogonal and compactly supported wavelets. Consequently, a long-term approximation (low frequency) and a short-term detail (high frequency) time series for the monthly precipitation obtained after 5th-level decomposition are investigated in terms of deterministic chaos theory. The data sets with low/high frequency components filtered by the wavelet transform are used for three-dimensional phase space analysis, respectively. Results show that both low and high frequency signals include clear chaotic signals and, therefore, might be governed by underlying dynamics based on different frequencies, respectively.
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| 2. |
- Jo, Ji Song, et al.
(författare)
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Anti-wrinkle activity of beta-carotene extracted & purified from recombinant Escherichia coli
- 2008
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Ingår i: KSBB Journal. - 1225-7117 .- 2288-8268. ; 23:6, s. 513-518
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Tidskriftsartikel (refereegranskat)abstract
- This paper described the extraction/purification of β-carotene from recombinant E.coli and evaluation of anti-wrinkle activity of purified β-carotene. No significant differences in extraction yields were observed when hexane or isobutyl acetate was used. However, extraction from wet-cell cake resulted in 2-fold higher amount of β-carotene than that from dry cells. Disruption of 5 g-wet cells by ultrasonic homogenizer, acetone dehydration, extraction with isobutyl acetate resulted in 36 mg of β-carotene corresponding to 61.2% of recovery. The formation and separation of ββ-carotene crystal improved the purity. 633 mg of β-carotene crystal with 93% purity was obtained from 223 g/L of wet-cell cake harvested from 2.5-L fed-batch culture broth. The cultures of normal human primary fibroblast were performed to investigate the effect of β-carotene on cytotoxicity as MTT assay and anti-wrinkle activity as collagen synthesis assays. 1.7μM of β-carotene was found to be optimal concentration at which 1.4-fold higher amount of collagen was synthesized than that in absence of β-carotene. This indicates that highly purified β-carotene can be obtained from recombinant E.coli by applying simple method with less toxic solvent and can be used in functional cosmetics as anti-wrinkle agent.
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| 3. |
- Ju, Jin Sung, et al.
(författare)
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A novel 40-kDa protein containing six repeats of an epidermal growth factor-like domain functions as a pattern recognition protein for lipopolysaccharide
- 2006
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Ingår i: Journal of Immunology. - 0022-1767 .- 1550-6606. ; 177:3, s. 1838-1845
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Tidskriftsartikel (refereegranskat)abstract
- Determination of structures and functions of pattern recognition proteins are important for understanding pathogen recognition mechanisms in host defense and for elucidating the activation mechanism of innate immune reactions. In this study, a novel 40-kDa protein, named LPS recognition protein (LRP), was purified to homogeneity from the cell-free plasma of larvae of the large beetle, Holotrichia diomphalia. LRP exhibited agglutinating activities on Escherichia coli, but not on Staphylococcus aureus and Candida albicans. This E. coli-agglutinating activity was preferentially inhibited by the rough-type LPS with a complete core oligosaccharide. LRP consists of 317 aa residues and six repeats of an epidermal growth factor-like domain-Recombinant LRP expressed in a baculovirus system also showed E. coli agglutination activity in vitro and was able to neutralize LPS by inhibition of LPS-induced IL-6 production in mouse bone marrow mast cells. Furthermore, E. coli coated with the purified LRP were more rapidly cleared in the Holotrichia larvae than only E. coli, indicating that this protein participates in the clearance of E. coli in vivo. The three amino-terminal epidermal growth factor-like domains of LRP, but not the three carboxyl epidermal growth factor-like domains, are involved in the LPS-binding activity. Taken together, this LRP functions as a pattern recognition protein for LPS and plays a role as an innate immune protein.
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| 4. |
- Kang, Jinho, et al.
(författare)
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Application of a 1H nuclear magnetic resonance (NMR) metabolomics approach combined with orthogonal projections to latent structure-discriminant analysis as an efficient tool for discriminating between Korean and Chinese herbal medicines
- 2008
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Ingår i: Journal of Agricultural and Food Chemistry. - Washington : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 56:24, s. 11589-11595
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Tidskriftsartikel (refereegranskat)abstract
- Correct identification of the origins of herbal medical products is becoming increasingly important in tandem with the growing interest in alternative medicine. However, visual inspection of raw material is still the most widely used method, and newer scientific approaches are needed. To develop a more objective and efficient tool for discriminating herbal origins, particularly Korean and Chinese, we employed a nuclear magnetic resonance (NMR)-based metabolomics approach combined with an orthogonal projections to latent structure-discriminant analysis (OPLS-DA) multivariate analysis. We first analyzed the constituent metabolites of Scutellaria baicalensis through NMR studies. Subsequent holistic data analysis with OPLS-DA yielded a statistical model that could cleanly discriminate between the sample groups even in the presence of large structured noise. An analysis of the statistical total correlation spectroscopy (STOCSY) spectrum identified citric acid and arginine as the key discriminating metabolites for Korean and Chinese samples. As a validation of the discrimination model, we performed blind prediction tests of sample origins using an external test set. Our model correctly predicted the origins of all of the 11 test samples, demonstrating its robustness. We tested the wider applicability of the developed method with three additional herbal medicines from Korea and China and obtained very high prediction accuracy. The solid discriminatory power and statistical validity of our method suggest its general applicability for determining the origins of herbal medicines.
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| 5. |
- Sung, Ki Won, et al.
(författare)
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Apparatus and Method for Reallocating Segments in Broadband Wireless Communication System
- 2006
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Patent (populärvet., debatt m.m.)abstract
- An apparatus and a method for reallocating segments in a broadband wireless communication system are provided. An average density for all cells in system and an average minimal inter-cell distance R are computed. A circle is determined having a radius kR and a center at a corresponding cell by increasing a constant k until a density of the circle becomes less than or equal to the average density. A cluster is generated for each cell, which is composed of cells included in the determined circle. Accordingly, segment allocation capability can be improved while minimizing a width of segment reallocation.
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| 6. |
- Sung, Ki Won, et al.
(författare)
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Determination of the Multi-slot Transmission in Bluetooth Systems with the Estimation of the Channel Error Probability
- 2006
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Ingår i: Wireless Communications & Mobile Computing. - : Wiley. - 1530-8669 .- 1530-8677. ; 6:1, s. 61-68
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Tidskriftsartikel (refereegranskat)abstract
- Bluetooth is an open specification for a technology to enable short-range wireless communications that operate in an ad hoc fashion. Bluetooth uses frequency hopping with a slot length of 625 Όs. Each slot corresponds to a packet and multi-slot packets of three or five slots can be transmitted to enhance the transmission efficiency. However, the use of multi-slot packet may degrade the transmission performance under high channel error probability. Thus, the length of multi-slot should be adjusted according to the current channel condition. Segmentation and reassembly (SAR) operation of Bluetooth enables the adjustment of the length of multi-slot. In this paper, we propose an efficient multi-slot transmission scheme that adaptively determines the optimal length of slots of a packet according to the channel error probability. We first discuss the throughput of a Bluetooth connection as a function of the length of a multi-slot and the channel error probability. A decision criteria which gives the optimal length of the multi-slot is presented under the assumption that the channel error probability is known. For the implementation in the real Bluetooth system, the channel error probability is estimated with the maximum likelihood estimator (MLE). A simple decision rule for the optimal multi-slot length is developed to maximize the throughput. Simulation experiment shows that the proposed decision rule for the multi-slot transmission effectively provides the maximum throughput under any type of channel error correlation.
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| 7. |
- Sung, Ki Won, et al.
(författare)
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Downlink Capacity Analysis of Collaborative Crossed Timeslots in CDMA TDD Systems
- 2009
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Ingår i: Wireless personal communications. - : Springer Netherlands. - 0929-6212 .- 1572-834X. ; 50:4, s. 469-481
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Tidskriftsartikel (refereegranskat)abstract
- Traffic asymmetry between uplink and downlink is expected to be a remarkable 3G characteristic in cellular mobile multimedia communications. CDMA system with TDD is a good solution to this traffic asymmetry. However, the level of traffic asymmetry may be significantly different from a cell to another cell. To tackle this problem and to support the traffic hot spot, crossed slots are examined. The use of crossed slots is restricted within a certain range of a cell by investigating the inter-cell interference and the maximum planned load factor. We examine the radius of inner zone and discuss the capacity of downlink crossed slots for various neighbor cell environments. Computational results show that the capacity increase in the target cell is outstanding by reducing the service range of neighbor cells. When all six neighbors reduce their service range by 20%, the capacity at target cell crossed slot is increased by 35%. Monte Carlo simulation is performed with large scale fading to verify the numerical analysis.
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