• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.871-878
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• 2004

Pulsed electric fields(PEF) technology is one of the latest nonthermal methods of food processing for obtaining safe and minimally processed foods. This technology can be effectively explored for obtaining safe food with minimum effect on nutritional, flavor, rheological and sensory qualities of food products. The process involves the application of high voltage(typically 20 ${\sim}$ 80 kv/cm) to foods placed between two electrodes. The mode of inactivation of microorganism; by PEP processing has been postulated in term; of electric breakdown and electroporation. The extent of destruction of microorganisms in PEF processing depends mainly on the electric field strength of the pulses and treatment time. For each cell types, a specific critical electric field strength and specific critical treatment time are required depending on the cell characteristics and the type and strength of the medium where they have been present. The effect also depends on the types of microorganisms and their phase of growth. A careful combination of processing parameters has to be selected for effective processing. The potential applications of PEF technology are numerous ranging from biotechnology to food preservation. With respect to food processing, it has already been established that, the technology is non-thermal in nature, economical and energy efficient, besides providing minimally processed foods. This article gives a brief overview of this technology for food processing applications.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1086-1092
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• 2012

It has been studied for DGPS/INS(Differential Global Positioning System/Inertial Navigation System) to offer the more precise and reliable navigation data with the aviation industry development. The flight performance evaluation of navigation system is very significant because the reliability of navigation data directly affect the safety of aircraft. Especially, the high-level navigation system, as DGPS/INS, need more precise flight performance evaluation method. The performance analysis is performed by comparing between the DGPS/INS navigation data and reference trajectory which is more precise than DGPS/INS. The GPS receiver, which is capable of post-processed CDGPS(Carrier-phase DGPS) method, can be used as reference system. Generally, the DGPS/INS is estimated the CG(Center of Gravity) point of aircraft while the reference system is output the position of GPS antenna which is mounted on the outside of aircraft. For this reason, estimated error between DGPS/INS and reference system will include the error due to lever arm. In order to more precise performance evaluation, it is needed to compensate the lever arm. This paper presents procedure and result of flight test which includes lever arm compensation in order to verify reliability and performance of DGPS/INS more precisely.

• Journal of Broadcast Engineering
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• v.15 no.1
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• pp.29-39
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• 2010

This paper presents and analyzes laboratory test results of distributed translator (DTxR) for distributed frequency network (DFN) in the ATSC (Advanced Television Systems Committee) terrestrial digital TV broadcasting system. The DTxR laboratory test is classified to receiving part test and transmitting part test. The receiving part test includes dynamic range, random noise, single echo, and adjacent channel interference. The transmitting part test includes quality of output signal (out-of channel emission, quality of transmitting signal, and phase noise), frequency synchronization among output signals, and TxID (Transmitter Identification) signal's affect to the legacy receiver. By the laboratory test results, the receiving part of DTxR eliminates average -2.5 dB of single echo and has average 17.5 dB at TOV (Threshold of Visibility) under random noise environment. In addition, the transmitting part of DTxR satisfies the specification of US FCC (Federal Communications Commission), and frequency difference among DTxR output signals is less than 0.001 Hz.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.164-170
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• 2007

The concept of innate immunity in insects which refers to the first line of host defense constitutes the humoral and cellular components which are involved in recognition and actively participate in the elimination of the intruding foreign micro- or macro-organisms. Several recent studies suggest that juvenile hormone (JH) modulates the cellular immune reactions in response to pathogen. In this study, pyriproxyfen (a JH agonist as an insect growth regulator) was tested in its any inhibitory effect on the immune reactions of the beet armyworm, Spodoptera exigua. To this end, five different hemocyte morphotypes of final instar S. exigua were identified by phase contrast microscopy. Plasmatocytes and granular cells, which constitute about 90% of the total hemocyte count, were prominently distinguished based on their basophilic/acidophilic nature using Giemsa stain. The role of pyriproxyfen on the functional ability of hemocytes was analyzed using FITC-labeled Providencia vermicola for the phagocytic potential of the hemocytes. Both granular cells and plasmatocytes exhibited phagocytosis behavior. Pyriproxyfen significantly inhibited the phagocytosis of both cell types, proposing its novel action as an immunosuppressant.

• Magazine of the Korean Society of Agricultural Engineers
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• v.26 no.4
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• pp.52-65
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• 1984

In general precise estimation of hourly of daily distribution of the long-term run-off should be very important in a design of source of irrigation. However, there have not been a satisfying method for forecasting of stationar'y long-term run-off in Korea. Solving this problem, this study introduces unit-hydrograph method frequently used in short-term run-off analysis into the long-term run-off analysis, of which model basin was selected to be Sumgin-river catchment area. In the estimation of effective rainfall, conventional method neglects the Soil moisture condition of catchment area, but in this study, the initial discharge (qb) occurred just before rising phase of the hydrograph was selected as the index of a basin soil moisture condition and then introduced as 3rd variable in the analysis of the reationship between cumulative rainfall and cumulative loss of rainfall, which built a new type of separation method of effective rainfall. In next step, in order to normalize significant potential error included in hydrological data, especially in vast catchment area, Snyder's correlation method was applied. A key to solution in this study is multiple correlation method or multiple regressional analysis, which is primarily based on the method of least squres and which is solved by the form of systems of linear equations. And for verification of the change of characteristics of unit hydrograph according to the variation of a various kind of hydrological charateristics (for example, precipitation, tree cover, soil condition, etc),seasonal unit hydrograph models of dry season(autumn, winter), semi-dry season (spring), rainy season (summer) were made respectively. The results obtained in this study were summarized as follows; 1.During the test period of 1966-1971, effective rainfall was estimated for the total 114 run-off hydrograph. From this estimation results, relative error of estimation to the ovservation value was 6%, -which is mush smaller than 12% of the error of conventional method. 2.During the test period, daily distribution of long-term run-off discharge was estimated by the unit hydrograph model. From this estimation results, relative error of estimation by the application of standard unit hydrograph model was 12%. When estimating by each seasonal unit bydrograph model, the relative error was 14% during dry season 10% during semi-dry season and 7% during rainy season, which is much smaller than 37% of conventional method. Summing up the analysis results obtained above, it is convinced that qb-index method of this study for the estimation of effective rainfall be preciser than any other method developed before. Because even recently no method has been developed for the estimation of daily distribution of long-term run-off dicharge, therefore estimation value by unit hydrograph model was only compared with that due to kaziyama method which estimates monthly run-off discharge. However this method due to this study turns out to have high accuracy. If specially mentioned from the results of this study, there is no need to use each seasonal unit hydrograph model separately except the case of semi-dry season. The author hopes to analyze the latter case in future sudies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.346-353
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• 2016

In the design conditions of some research reactors, the siphon phenomenon can cause continuous efflux of water during pipe rupture. A siphon breaker is a safety device that can prevent water efflux effectively. However, the analysis of the siphon breaking is complicated because many variables must be included in the calculation process. For this reason, a simulation program was developed with a user-friendly GUI to analyze the siphon breaking easily. The program was developed by MFC programming using Visual Studio 2012 in Windows 8. After saving the input parameters from a user, the program proceeds with three steps of calculation using fluid mechanics formulas. Bernoulli's equation is used to calculate the velocity, quantity, water level, undershooting, pressure, loss coefficient, and factors related to the two-phase flow. The Chisholm model is used to predict the results from a real-scale experiment. The simulation results are shown in a graph, through which a user can examine the total breaking situation. It is also possible to save all of the resulting data. The program allows a user to easily confirm the status of the siphon breaking and would be helpful in the design of siphon breakers.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.1
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• pp.44-48
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• 2003

Experiments were carried out to investigate the elimination of cadmium in tissues (gill, intestine, liver, kidney and muscle) of flounder, Paralichthys olivaceus, after sub-lethal Cd exposure (5, 50, 100 ${\mu}g/L$). During the depuration phase, Cd concentration in the gill decreased immediately following the end of the exposure period. The elimination rates at the end of depuration periods were $18\%$ for 50 ${\mu}g/L$ exposure and $70\%$ for 100 ${\mu}g/L$ exposure. Intestine showed fastest elimination rates of Cd at all concentration. At the end of the depuration period, the Cd concentration was similar to that in the control, Cd elimination in liver significantly decreased after 10 days of depuration period. After 20 days of depuration, the elimination rate was $66.20\%$ in the fish exposed to 50 ${\mu}g/L$ and $86.22\%$ in the fish exposed to 100${\mu}g/L$. The order of cadmium elimination in tissues were decreased intestine>liver${\geq}$gill>>kidney during depuration periods. In this study the gill, intestine and liver showed faster elimination rate of Cd in 50, 100 ${\mu}g/L$-Cd exposure concentration. After the end of the Cd exposure, the Cd concentration in the kidney slowly decreased or remained constant and the Cd concentration in the muscle slowly increased or remained constant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1783-1788
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• 2009

We newly propose that we may reuse scrap powders ($Z_rO_2$+8 mol%-$Y_2O_3$) as $Y_2O_3$-stabilized zirconia (YSZ) sintered products through sintering process at 1550$^{circ}C$ for 2hrs. We also prepared the reference specimen from fresh $Z_rO_2$+30 mol%-$Y_2O_3$ powder mixture (celluar type with 1㎛-length). The reference sample showed a dense microstructure with grains of $\sim$10㎛ in diameter, while the sintered sample from scrap powder showed irregular grains of 1$\sim$30 ㎛ in diameter. Through XRD analysis, we confirmed that the reference sample has mixed phases of $Y_2O_3$(cubic), $Z_{r0.8}O_{1.9}$(cubic), and $Z_rO_2$(monoclinic), while the sintered YSZ sample from scrap powder has only tetragonal phase. Moreover, the sintered YSZ from scrap powder showed vickers hardness and apparent density more than 70 and 4.11 g/cc, which implies that it can be suitable for structural material application.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.11
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• pp.1031-1040
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• 2010

Hash join is one of the core algorithms in databases management systems. If a hash join cannot complete in one-pass because the available memory is insufficient (i.e., hash table overflow), however, it may incur a few sequential writes and excessive random reads. With harddisk as the tempoary storage for hash joins, the I/O time would be dominated by slow random reads in its probing phase. Meanwhile, flash memory based SSDs (flash SSDs) are becoming popular, and we will witness in the foreseeable future that flash SSDs replace harddisks in enterprise databases. In contrast to harddisk, flash SSD without any mechanical component has fast latency in random reads, and thus it can boost hash join performance. In this paper, we investigate several important and practical issues when flash SSD is used as tempoary storage for hash join. First, we reveal the va patterns of hash join in detail and explain why flash SSD can outperform harddisk by more than an order of magnitude. Second, we present and analyze the impact of cluster size (i.e., va unit in hash join) on performance. Finally, we emperically demonstrate that, while a commerical query optimizer is error-prone in predicting the execution time with harddisk as temporary storage, it can precisely estimate the execution time with flash SSD. In summary, we show that, when used as temporary storage for hash join, flash SSD will provide more reliable cost estimation as well as fast performance.

• Journal of the Korean Institute of Gas
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• v.7 no.2 s.19
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• pp.22-32
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• 2003

Al-brass material is generally used at the state of plastic deformation, for example; bending, extension of bell mouth at shell and tube type heat exchanger. And SCC(stress corrosion cracking) of Al-brass material will be affected by residual stress as plastic deformation. SCC results from synergism between mechanical factor and corrosion environment. Mechanical factor is stress that directly relates with stress intensity factor at the crack tip. This paper was studied on the effect of stress on SCC of Al-brass tube under in $3.5\%$ NaCl. + $0.1\%\;NH_4OH$ solution by constant displacement tester. Increasing of acidified water flow into sea and speeds up corrosion rate of Al-brass which is used as a tube material of vessel heat exchanger by polluted coast seawater. The experimental results are as follow The latent time of SCC occurrence gets longer as the initial stress intensity factor($K_{Ii}$) gets lower The main crack was propagated as the initial stress intensity factor($K_{Ii}$) gets higher, and secondary cracks occurred by electro-chemical factor a(ter stage of released stress. Dezincification phase showed around the crack, and the range of dezincification gets wider as the initial stress intensity factor($K_{Ii}$) gets higher.