• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.543-550
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• 2002

This paper proposes the dynamic slot allocation method for real-time VBR (rt-VBR) services in wireless ATM networks. The proposed method is characterized by a contention-based mechanism of the reservation request, a contention-free polling scheme for transferring the dynamic parameters. The base station scheduler allocates a dynamic parameter minislot to the wireless terminal for transferring the residual lifetime and the number of requesting slots as the dynamic parameters. The scheduling algorithm uses a priority scheme based on the maximum cell transfer delay parameter. Based on the received dynamic parameters, the scheduler allocates the uplink slots to the wireless terminal with the most stringent delay requirement. The simulation results show that the proposed method guarantee the delay constraint of rt-VBR services along with its cell loss rate significantly reduced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1136-1144
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• 2010

In this paper, the effects of HARQ feedback error are evaluated in IEEE 802.16m system when the HARQ and ARQ interactions that utilize the HARQ feedback information is used. Also, the HARQ and ARQ interaction scheme considering HARQ feedback errors are proposed. The HARQ and ARQ interaction scheme improve the system throughput by using the HARQ feedback information instead of the ARQ feedback message, which reduce retransmission time. However, errors in the HARQ feedback information generate severe performance degradation. Especially, the local NAK errors between HARQ feedback error critically degrade the performance, because the local NAK errors lead the loss of ARQ blocks. We propose a channel state-based schemes for HARQ and ARQ interactions to mitigate the throughput degradation due to HARQ feedback errors. Simulation results show that the proposed scheme improves the throughput and the delay performance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.344-349
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• 2001

The removal of chlorine from aqueous solutions on dried Chlorella vulgaris(DCV) and green tea powder(GTP) were investigated as a function of contact time, pH and initial chlorine concentration. Removal by DCV and GTP reached equilibrium after 3hrs and 0.5hr, respectively. Optimum removal pH values of DCV and GTP were determined as above 10. Both Langmuir and Freundlich adsorption models were suitable for describing the short-term removal of chlorine by DCV and GTP. According to Langmuir adsorption isotherms the maximum removal capacity of DCV (2.75mg $Cl_2/mg$) was nearly two times greater than those of GTP (1.53mg $Cl_2/mg$) and activated carbon (1.47mg $Cl_2/mg$). These results suggested that Chlorella vulgaris biomass might potentially be used as an alternative to traditional water treatment materials for removal of residual chlorine in drinking water or process waste-water.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.66-71
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• 2006

Fluoroquinoles have a wide range of antimicrobial properties and are effective in the treatment of bacterial diseases in fish. The use of fluoroquinoles continues to grow steadily. Fluoroquinolone antibiotics are probably the most important class used among synthetic antibiotics in human and veterinary medicines because of their broad activity spectrum and good oral absorption. This study was conducted to estimate the residue of antibiotics in four species of farmed fishes, including olive flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagrus major), and sea bass (Lateolabrax japonicus), collected from fish farms located in the southern coastal area of Korea. The residues of fluoroquinolones were determined using high performance liquid chromatography (HPLC) with a fluorescence detector. Residuals of five fluoroquinolones in muscle tissue of farmed fish were analyzed. We found that enrofloxacin was the most common agent in fish muscle, and that ciprofloxacin was the next most common. The range of detected concentrations of fluoroquinolones in olive flounder muscle was 0-0.859 mg/kg in 32.6% of all samples. Enrofloxacin was commonly detected in sea bass muscle at a range of 0-0.143 mg/kg in 38.9% of all samples. Fluoroquinolones were detected in 6.9% of black rock fish muscle and in 16.6% of sea bream, although the detected concentration was below 0.01 mg/kg. The maximum detection value of enrofloxacin and ofloxacin in olive flounder at the time of shipping was 0.102 mg/kg and 0.09 mg/kg, respectively; no other antimicrobials were detected. We detected no antimicrobial substances in red sea bream.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.929-936
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• 2013

The saturator and injection nozzle are important facilities on the dissolved air flotation process. To increase the formation of micro bubble, it is required to improve the air dissolving performance in the saturator and keep the pressure uniform from the saturator to the nozzle. This study aimed to evaluate the performance of the saturator and the hydraulic effect of the nozzle and the pipe structure. The air volume concentration, bubble size and bubble residual time were measured in the test. The saturator, which had mounted with the spray nozzle, showed a good performance for bubble formation. Also, the characteristics of micro bubble formation were influenced by pressure uniformity and flow velocity through the orifice in the nozzle.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.235-242
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• 1999

We investigated the growth-inhibitory mechanism of Helicobacter pylori by omeprazole (OMP) and its activated sulfenamide (OAS). Using dithiothreitol (DTT) and 5,5'-dithio-bis[2-nitrobenzoic acid] (DTNB; Ellman's reagent), we first determined the relationship between the binding capacity of these compounds to H. pylori membrane and its significance to membrane P-type ATPase activity. After incubation of the intact H. pylori cells with either OMP or OAS, the residual quantity of free SH-groups on the cell membrane was measured, and, the resulting values were plotted as a function of time. From this experiment, we found that there was a considerable difference in the membrane-binding rates between OMP and OAS. At neutral pH, the disulfide bond formation on H. pylori membrane was completed within 2 min of incubation of the intact cells with OAS. By OMP, however, it was gradually formed, exceeding 10 min of incubation for completion, whereby, the extent of P-type ATPase inhibition appeared to be proportional to the disulfide forming rate. From this data, it was suggested that the disulfide formation might directly affect enzyme activity. Since OMP per se cannot yield a disulfide bond with cysteine, it is predicted that the enzyme inactivation must be caused by the OAS form. Accordingly, we postulated that, under the neutral pH, OMP could be converted to OAS in the course of transport. By extrapolating the inhibitory slopes, we could evaluate K₁ values, relating to their minimal inhibitory concentrations (MICs) for H. pylori growth. In these MIC ranges, H. pylori uptake or vesicular export of nutrients such as peptides were totally prohibited, but their effect in Escherichia coli were negligible. From these observations, we strongly suggest that the P-type ATPase activity is essential for the survival of H. pylori cells in particular.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.53-60
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• 1998

The influence of venting on the leaching characteristics of pure gasoline and gasoline contaminated soil was studied. The change of leaching characteristics by venting of contaminated soil column could be characterized by two distinct trends : 1) the leaching concentration in TPH-GRO rapidly decreased with evaporation until the evaporation loss became 75% of the original volume. Afterwards, it gradually decreased. 2) the leaching concentrations of individual components showed initial increase followed by gradual decrease. In general, the relative increase of leaching concentration and the venting time to reach the maximum increased with the molecular weight of the components. It should be noted that the decrease of gasoline concentration in the vented air occurs faster than that in the leaching solution. This indicates that, after removing most of the gasoline by evaporation, the focus of the risk assessment for the residual contaminants should be on the groundwater contamination rather than air pollution.

• Journal of Chest Surgery
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• v.27 no.12
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• pp.989-994
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• 1994

Between January 1986 and August 1993, 11 patients underwent surgical repair of ventricular septal defect [VSD] complicated with myocardial infarction. The ages of patients were ranged from 22 years to 83 years with a mean of 64 years. There were 8 male and 3 female patients. The preoperative cineangiograms of all patients were reviewed to measure both ventricular function and to evaluate coronary artery disease. The mean time interval between occurance of VSD and operation was 13 days. The operations were performed as soon as possible if there were hemodynamic derangement. Postmyocardial infarction VSD were repaired simultaneuously with coronary artery bypass graft in 3 patients, repaired with left ventricular aneurysmectomy in 6 patients, with left ventricular thrombectomy in 1 patient and with mitral valve chordae repair in 1 patient. There was no early death [within 30 days]. There were 6 postoperative complications; one with perioperative myocardial infarction, two with recurred VSD on postoperative 1 and 6 days respectively, two with lower leg embolism associated with intraaortic balloon pump insertion, one with wound infection. Of the complicated patients, 1 patient with lower leg embolism performed left above ankle amputation. Among two patients with recurred ventricular septal defect, one patient is doing well without problem. On follow up echocardiogram, the residual VSD was occluded completely. However another patient was with recurred VSD died 3 months after the operation because of congestive heart failure. Of the long term survivors, all patients are in NEW YORK Heart Association functional Class I or II. Although number of patients were small, our results of surgical closure of postmyocardial infarction VSD were favored to the others. Moreover, seven patients with preoperative cardiogenic shock among 11 were performed early operation after diagnosis of ventricular septal rupture. All of the patients were survived and doing well during the follow up period. Therefore early diagnosis with aggressive preoperative care with intraaortic balloon pumping and early operation seems to be very important for prevention of deterioration of vital organ.

• Journal of the Korean Wood Science and Technology
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• v.24 no.3
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• pp.18-27
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• 1996

The feasibility of using stress-wave technique in the transverse direction for the assessment of early stages of decay was investigated using compression test specimens having different annual ring orientations subjected to decay by Tyromyces palustris for various time intervals. Decay detection, quantitative assessment of decay, and the prediction of residual strength of decayed wood with less than five percent weight loss can be feasible using stress-wave parameters (wave velocity, wave impedance, and stress-wave elasticity) and their percent reduction due to decay, measured by stress-wave technique in the transverse direction. The use of stress-wave technique in the transverse direction for the application of this technique to structural members in service is desirable, when considering the easiness of attachment of accelerometers of stress-wave measuring device on the surface of members and also accurate detection of localized decayed areas. In stress-wave technique in the transverse direction, stress-wave parameters measured were different according to the angles between wave propagation path and annual ring, due to the anisotropy of wood structure. Therefore, it is recommended to use percent reduction in stress-wave parameters instead of stress-wave parameters. This evaluation method using percent reduction in stress-wave parameters is ideal when it is impossible to observe annual ring orientation on the transverse surface of wood.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.335-335
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• 2011

Instability of a thin film attached to a compliant substrate often leads to emergence of exquisite wrinkle patterns with length scales that depend on the system geometry and applied stresses. However, the patterns that are created using the current techniques in polymer surface engineering, generally have low aspect ratio of undulation amplitude to wavelength, thus, limiting their application. Here, we present a novel and effective method that enables us to create wrinkles with a desired wavelength and high aspect ratio of amplitude over wavelength as large as to 2.5:1. First, we create buckle patterns with high aspect ratio of amplitude to wavelength by deposition of an amorphous carbon film on a surface of a soft polymer poly(dimethylsiloxane) (PDMS). Amorphous carbon films are used as a protective layer in structural systems and biomedical components, due to their low friction coefficient, strong wear resistance against, and high elastic modulus and hardness. The deposited carbon layer is generally under high residual compressive stresses (~1 GPa), making it susceptible to buckle delamination on a hard substrate (e.g. silicon or glass) and to wrinkle on a flexible or soft substrate. Then, we employ glancing angle deposition (GLAD) for deposition of a high aspect ratio patterns with amorphous carbon coating on a PDMS surface. Using this method, pattern amplitudes of several nm to submicron size can be achieved by varying the carbon deposition time, allowing us to harness patterned polymers substrates for variety of application. Specifically, we demonstrate a potential application of the high aspect wrinkles for changing the surface structures with low surface energy materials of amorphous carbon coatings, increasing the water wettability.