• Bulletin of the Korean Chemical Society
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• v.5 no.4
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• pp.154-158
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• 1984

In order to characterize the permeability of small unilamellar vesicles (SUV), efflux of 6-carboxyfluorescein (6-CF) from the vesicles was monitored spectrophotofluorometrically. Since the entrapped highly quenched 6-CF (200 mM) became fluorescent upon release from the vesicles, the 6-CF could be used as an efflux probe. SUV containing entrapped 6-CF was prepared from egg phosphatidylcholine and separated by gel filtration on Sepharose 4B. Observed change of relative fluorescent intensity with time was sigmoidal. From this curve, the parameter of permeability was determined either by half-time or a released amount per unit time from the initial slope. Half-time of efflux of prepared SUV having 302 ng phospholipid/ml in 10 mM Tris-HCl buffer pH 7.4 was 21.0 min at $37{\circ}C$. Various factors which could affect the half-time were examined including temperature, pH, salt, and vesicle concentration. In particular the effect of vesicle concentration on the efflux revealed that the permeability can be a function of the concentration.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.251-258
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• 2022

Silk fibroin microparticles were fabricated using a phase separation technique between silk fibroin solution and polyvinyl alcohol. We found that the concentration of polyvinyl alcohol determines the size of microparticles. The mean diameter of the silk fibroin microparticles varied from 3.48 ㎛ to 4.05 ㎛. The silk fibroin microparticle size increased as a function of the concentration of PVA in aqueous silk solution. The resulting silk fibroin microparticles have narrow size distribution (i.e. monodisperse) and smooth/spherical surface. Also, we studied the effects of mouse serum, sodium phosphate buffer (PBS), and pH on the stability of the silk fibroin microparticles. Overall, we demonstrated the simple method to fabricate and to control the silk fibroin microparticles that makes our silk microparticles to be usable for a potential drug delivery carrier.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1986.04a
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• pp.119-124
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• 1986

This paper describes the development of the KORNET that may be regarded as the latest public packet-swiched computer communication network. The KORNET project included the development of the network management center (NMC), a network concentrator. For the KORNET we use the virtual circuit(VC) method, a distributed adaptive routing algorithm, and a dynamic buffer management algorithm. The NMC acts as a nerve center of the network, performing such function as network monitoring, subscriber and network management and routing management, etc. As for the NNP and NC hardware, we have implemented them with the 16-bit multitask/multiprocessor technology using MC68000 microprocessors. Softwares have been developed using C language is required for real time processing. All the network protocols we have developed comply completely with the latest CCITT recommendations including X.25, X,3 , X.28 and X.29.

• Asian Journal of Business Environment
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• v.14 no.2
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• pp.19-30
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• 2024

Purpose: This research article investigates the intricate relationship between economic growth and employment in the Korean agri-food industry. Research design, data and methodology: Drawing on Okun's law, which proposes a negative correlation between economic growth and unemployment, the study explores the applicability of this law to different sectors. By focusing on the agri-food industry, the study examines the impact of economic growth on both full-time and temporary employment. Results: The findings highlight the industry's role as a buffer, absorbing workers from other sectors, particularly manufacturing. Moreover, the study reveals that temporary employment is more sensitive to economic growth fluctuations compared to full-time employment. Conclusions: The research emphasizes the importance of implementing employment programs that support transitioning workers in the agri-food industry, facilitating knowledge and skill transfer to ensure sustained employment. Furthermore, it recommends government and company support for temporary employment during buffering periods to ensure safe job transitions. This study provides valuable evidence to understand the nuanced relationship between economic growth and employment in the Korean agri-food industry.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.3
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• pp.17-28
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• 2003

The objective of this study is to review and verify whether the functions and effect of roadside trees generally known in theory are actually realized in urban roads and how well they are performed if the function and effect are really realized. The study was conducted with a focus on air purification effect of roadside trees. The m헤r study result is as follows. First, calculation of air purification effect of roadside trees showed that it is minimal. However, 7.4 units of broad-leaved trees is necessary in order to purify $SO_2$ discharged by one passenger car and 1,803.3 trees to purify $NO_2$. Second, regarding pollutant absorption capacity, air pollutant absorption capacity increased as the number of rows planted gets higher (i.e., 2-row plantation absorbs pollutant better than I-row plantation). In particular, "2-row plantation + lower-level shrub + buffer green belt" was as eight times high as "I-row plantation" in absorption capacity. Third, out of 30 roads with over 8 lanes in 15 cities, only 33.3% or a total of ten roads in seven cities had a median strip. Out of these ten roads, nine roads were planted in a double-layer consisting forest trees, shrubs, ground plants (grass). Analysis showed that out of six tree species planted along these roads, about a half of them were weak to air pollution. Also, based on the outcome of this study, charging a "plantation due" when people purchase a new car, improving layout of roadside trees, and reinforcing plantation of air purification tree species when selecting tree species for roadside trees were proposed.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.55-64
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• 2016

Existing Android applications for streaming video in real time are dependent on the codec, which composes the encoding function, and the version of Android operating system. Also, for streaming video in real time, most applications should be connected with a separate desktop PC. To overcome these disadvantages, we propose a new application, which records and streams video in real time. Specifically, the proposed application uses the flash video file format, which is the common media file format supported by various versions of Android operating system. Through experiments, we show that it is possible for the proposed application to record the video screens more than 20 frames per second and to stream it in real time while using the existing video encoding methods.

• The Transactions of the Korea Information Processing Society
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• v.3 no.7
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• pp.1880-1893
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• 1996

In this paper, we propose the fuzzy traffic control method in ABR service for the effective use of ATM link. This method, a modified version of EPRCA which is one of rate control methods in ABR service, controls the values of the transmission rates of source by using the fuzzy traffic inference based on switch buffer size and buffer variate rate. For this method, we developed a model and algorithm of the fuzzy traffic control method and a fuzzy traffic controller, after studying fuzzy and neural networks which applied to ATM traffic control and EPRCA. For the fuzzy traffic controller, we also designed a membership function, fuzzy control rules and a max-min inferencing method. We conducted a simulation and compared the link utilization of the fuzzy traffic control method with that of the EPRCA method. The results of the simulation indicated that, compared to EPRCA, the fuzzy traffic control method improves the link utilization by 2.3% in a normal distribution model and by 2.7% in the MMPP model of the source.

• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.433-438
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• 2007

We fabricated thin films of Au and Ta/Au with thicknesses of 30 nm and 5 nm/30nm, respectively on Si(100) or Si(111) substrates using a dc magnetron sputtering system. Grain sizes, roughness and conductivity for Au thin films are measured as a function of the annealing temperatures. We observed that the grain size of samples enlarged and the surface became rougher with increasing annealing temperature. The grain size and roughness were improved in the structure of Si/Ta/Au than Si/Au. Furthermore, the Si(100) substrate was more effective for decreasing the resistance for Ta/Au system than Si(111) substrate. We confirm that by inserting a Ta buffer layer in Si(100)/Au, surface roughness was reduced and by adjusting the annealing temperature the grain size were enlarged. Consequently, the Au thin-film has improved conductivity.

• Journal of Korea Multimedia Society
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• v.14 no.9
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• pp.1175-1181
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• 2011

Practice education using virtual medical simulation has been recently introduced to maximize the learning efficiency in clinical environment. Specially, in minimally invasive surgery, the necessity of virtual surgery medical simulation has been substantially increased. Since cauterizing effect occurred frequently in minimally invasive surgery has been represented by simple bleeding, realistic cauterizing effect animation has not been proposed yet. In this paper, we propose realistic real-time cauterizing effect animation. Proposed method changes the individual element of each vertex color of the mesh and uses sigmoid function to impose weights for the smooth color change inside the valid mesh region so that the results of cauterizing effect animation was realistic. In addition, by proposing cauterizing color buffer, overlapped cauterizing effects can be realistically represented. Proposed method greatly improves the sense of the real and absorption in virtual surgery medical simulation so that the education efficiency of doctors and students using medical simulation can be maximized.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.4
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• pp.17-24
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• 2004

Call blocking probabilities of streaming data service in CDMA system with access point(AP) of WLAN are analyzed for different cell geometry of base station and AP and queuing is modeled. The considered system leads to successful handoffs between the APs of WLAN. Blocking probabilities are enumerated as a function for ratio of base station and AP sizes, their locations and the number of buffer in the queue. Results show that blocking probability is not influenced by base station and AP locations but mainly by ratio of their sizes. For CDMA system of radius 100m, 5 buffers in the queue and 7㏈ noise rise(NR), in order to obtain 1% call blocking probability, a cell with hot spot of radius 20m has more 0.6Erlang than that of radius 60m.