• Environmental Engineering Research
• /
• v.10 no.6
• /
• pp.283-293
• /
• 2005

Characteristics of sulfur-based autotrophic denitrification in a semi-continuous type reactor and the kinetic parameters were studied. Enriched autotrophic denitrifying culture was used for the reactor operation. Biomass growth on sulfur particles and in the liquid medium was monitored using the DAPI staining method. From the result of ion concentration changes and the biomass growth, maximum specific growth rate, ${\mu}_{max}$, and the half velocity constant, $K_M$, were estimated as $0.61\;d^{-1}$ and 3.66 mg/L, respectively. Growth yield coefficient, Y values for electron acceptor and donor were found as 0.49 gVSS/g N and 0.16 gVSS/g S. The biomass showed specific denitrification rate, ranging 0.86-1.13 gN/g VSS-d. A half-order equation was found to best simulate the denitrification process in the packed bed reactor operated in the semi-continuous mode.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.531-534
• /
• 2010

Currently the functionality of the PRC-999K radio that is widely used in Korean Army is half-duplex and the broadcasting system that all subscribers have to listen when one subscriber speaks in time. Radio data communication system configures peer-to-peer network between command post and network members in military fire control system. And the system applies CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance) technique to avoid data collision. Such a data transmitting/receiving time could be reduced by allocating address in serial order to each network members. By doing that, command post need to broadcast data only one time and assigned members will reply in order without data collision. This paper provides such a protocol and algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.1
• /
• pp.350-364
• /
• 2022

Traditionally, in multi-user multi-carrier systems, the neighboring subband will be gapped by one subcarrier, which is set as guard band to reduce multiple access interference (MAI) between neighboring subbands. The empty subcarrier for guard band will degrade the spectral efficiency of the whole system. In order to enhance the spectral efficiency of multi-user filter bank multiple carrier (FBMC) systems, a new subband allocation method is introduced, in which the neighboring subband is gapped by half subcarrier instead of one subcarrier. Meanwhile, in order to implement the proposed resource allocation scheme, an optimized FBMC prototype filter is designed to decrease the inter-subband interference to the neighboring subband. The detailed simulations about the comparison between the proposed spectrum assignment and traditional FBMC are given, as well as the performance in the different interference scenarios. The simulation results show that the combination of the proposed spectrum assignment scheme and the optimized filter has better performance compared to the traditional scheme. The proposed scheme can be used in the system which serves massive users to get higher spectrum efficiency.

• Journal of the Korean Mathematical Society
• /
• v.46 no.6
• /
• pp.1243-1254
• /
• 2009

The inverse scattering problem is investigated for some second order differential equation with a nonlinear spectral parameter in the boundary condition on the half line [0, $\infty$). In the present paper the coefficient of spectral parameter is not a pure imaginary number and the boundary value problem is not selfadjoint. We define the scattering data of the problem, derive the main integral equation and show that the potential is uniquely recovered.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1999.11a
• /
• pp.181-183
• /
• 1999

This paper is about the design of half-bridge inverter controller with low cost and simple configuration for low power single-phase induction motor driving. The simple controller is composed of MCU and PLD. Also, to limit the overcurrent at initial driving, auxiliary function is added, and stabilizes the system. In order to verify the performance of the proposed methode, we design 500W inverter system, and in result, the response time of the proposed method compared with line voltage driving method is reduced by 200[msec].

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.1
• /
• pp.105-110
• /
• 2010

Purpose: Three phase bone scan was considered sensitive in Patients with Reflex Symphathetic Dystrophy Syndrome (RSDS). Generally, three phase bone scan in the RSDS patients shows increased uptake of one side extremity joint. But three phase bone scan has been performed with flow, blood pool and delayed scan. We performed blood pool half body scan in order to investigate its usefulness. Materials and Methods: From October 2007 to September 2009, three phase bone scan (flow, blood pool, half body blood pool, delayed) was performed after injection of 750 MBq of $^{99m}Tc$-DPD in diagnosed patients with RSDS (M:F=8:7, R:L=9:6). For quantitative analysis, we obtained the count ratios of bilateral hands by drawing a region of interest (ROI) in the three phase images and compared with the count ratios of shoulders in half body blood pool and delayed images. Results: In flow images, right/left ratios were $1.09{\pm}0.53$. In blood pool images, right/left ratios were $1.13{\pm}0.47$ (hand), $1.08{\pm}0.26$ (shoulder). In delayed images, right/left ratios were $1.24{\pm}0.75$ (hand), $1.11{\pm}0.31$ (shoulder). As a result, Log of right/left counts of the others and that of shoulder blood pool image were correlated well with statistical significance (Spearman's R, p<0.005 SPSS for windows ver.12.0). Conclusion: Half body blood pool scan may be helpful in the diagnosis of patients with RSDS. Moreover, Half body blood pool scan reduced false negative and false positive rates. In order to improve agreement on interpretation of RSDS, Blood pool half body scan should be established as common criteria.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.2
• /
• pp.260-264
• /
• 2005

The nature of the active site of Tobacco acetohydroxyacid synthase (AHAS) in the substrate- and cofactorbinding was studied by kinetics and fluorescence spectroscopy. The substrate saturation curve does not follow Michaelis-Menten kinetics at different temperatures (7, 21 and 37 ${^{\circ}C}$), pH (6.5, 7.5 and 8.5) and buffers (Tris-HCl and MOPS). The concentration of one half of the maximum velocity ($S_{0.5}$) decreased in the following order: pyruvate $\gt$ ThDP $\approx$$Mg^{+2}$ $\gt$ FAD. However, the catalytic efficiency (K$_{cat}/S_{0.5}$) inversely decreased in the following order; FAD $\gt$ $Mg^{+2}$ $\approx$ThDP $\gt$ pyruvate, indicating that the cofactors by in decreasing order; FAD, $Mg^{+2}$, ThDP, affect the catalysis of AHAS. The dissociation constant ($K_d$) of the intrinsic tryptophan fluorescence decreased with the same tendency of the concentration of one half of the maximum velocity ($S_{0.5}$) decreasing order. This data provides evidence that the substrate and cofactor binding natures of the active site, as well as its activation characteristics, resemble those of other ThDP-dependent enzymes.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.3
• /
• pp.690-700
• /
• 1994

The effects of thermal stratification on the flow of a stratified fluid past a circular cylinder were examined in a wind tunnel. In order to produce strong thermal stratifications, a compact heat exchanger type variable electric heater is employed. Linear temperature gradient of up to $250^{\circ}C/m$ can be well sustained. The velocity and temperature profiles in the cylinder wake with a strong thermal gradient of $200^{\circ}C/m$ were measured and the smoke wire flow visualization method was used to investigate the wake characteristics. It is found that the temperature field effects as an active contaminant, so that the mean velocity and temperature profiles can not sustain their symmetricity about the wake centerline when such a strong thermal gradient is superimposed. It is evident that the turbulent mixing in the upper half section is stronger than that of the lower half of the wake in a stably stratified flow.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.54-57
• /
• 2003

A new non linear, mean value, instantaneous following control technique to design half bridge converter is proposed in witch control principle uses characteristic that reset time of analog integrator is inverse proportion In input voltage. It is Important characteristic that compensation and follow-up control time are same with switching frequency. Is completed in one cycle that base control frequency. Have excellence characteristic that follow in order instruction value exactly stationary state as well as transient state. Half bridge converter that apply this control principle can know that have stabilize and excellence characteristic. This technique is verified through an experiment, and know that experiment result and theory agree well.

• The Research Journal of the Costume Culture
• /
• v.1 no.2
• /
• pp.145-157
• /
• 1993

This study aimes to investigate the garment ease of pe-school children's clothing in accordance with arm movement. The experiment was done with 4 per-school children fro mage 3 to age 5, and 3 types of experimental clothes were made ; sleeveless, half sleeve, and long sleeve. The waist pattern and the sleeve pattern of each experimental clothes has no garment ease. And experimental clothes were examined to obtain the necessary ease of armcye line and waist lien by cross-cut method. The results of investigation can be summarized as follows ; 1. The resulting movement ranges of experimental clothes with no garment ease were 131.5°(sleeveless), 71.75°(half sleeve), and 62.25°(long sleeve). 2. The size order of cross-cut opening of waist lien movement were (side>front>back), and (half sleeve>long sleeve>sleeveless). 3. When the base point of measurement was set to armpit point by arm the latitudinal length of cross-cut opening of armcye line by arm movement was (anterior armpit part > posterior armpit part), and longitudinal length of cross-cut opening was (upper part>lower part).