• Tunnel and Underground Space
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• v.34 no.1
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• pp.1-14
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• 2024

An image-reconstruction technology, involving the deployment of an unmanned mobility equipped with high-speed LiDAR (Light Detection And Ranging) has been proposed to reconstruct the shape of abandoned mine. Unmanned mobility operation is remarkably useful in abandoned mines fraught with operational difficulties including, but not limited to, obstacles, sludge, underwater and narrow tunnel with the diameter of 1.5 m or more. For cases of real abandoned mines, quadruped robots, quadcopter drones and underwater drones are respectively deployed on land, air, and water-filled sites. In addition to the advantage of scanning the abandoned mines with 2D solid-state lidar sensors, rotation of radiation at an inclination angle offers an increased efficiency for simultaneous reconstruction of mineshaft shapes and detecting obstacles. Sensor and robot posture were used for computing rotation matrices that helped compute geographical coordinates of the solid-state lidar data. Next, the quadruped robot scanned the actual site to reconstruct tunnel shape. Lastly, the optimal elements necessary to increase utility in actual fields were found and proposed.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.53-63
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• 2024

Adopting an engine igniter with high efficiency and ignition performance is essential for reliable operation of liquid rocket engines. In this study, we developed a spark torch igniter for a 450 N-scale methane-oxygen liquid rocket engine by conducting numerical analyses, igniter manufacturing and validation. Specifically, we conducted a parametric study for maximizing the enthalpy at the igniter exit, specifically by adjusting the mass flow rate, nozzle area ratio, fuel-oxidizer mixture ratio, and the igniter length-to-diameter. The heat transferred via the igniter nozzle exit was computed using 3-dimensional numerical simulations. We also manufactured and tested the igniter based on a deduced design to confirm ignition performance of the designed spark torch igniter. The igniter developed through this study could contribute to the development of practical propulsion systems such as upper-stage engines of small launch vehicles.

• Membrane Journal
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• v.34 no.1
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• pp.38-49
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• 2024

Wastewater treatment using membrane bioreactors has been extensively used to alleviate water shortage and pollution by improving the quality of the treated water discharged into the environment. However, membrane biofouling persistently holds back an MBR process by reducing the process efficiency. Herein, we synthesized carbon nanospheres (CNSs) with many hydrophilic oxygen groups and utilized them as an additive to prepare high-performance ultrafiltration (UF) membranes with hydrophilicity and porous pore structure. CNSs were found to form crescent-shaped pores on the membrane surface, increasing the mean surface pore size by about 40% without causing significant defects larger than bubble points, as the CNS content increased by 4.6 wt%. In addition, the porous pore structure of CNS composite membranes was also attributable to the CNS's isotropic morphologies and relatively low particle number density because the aforementioned properties contributed to preventing the polymer solution viscosity from soaring with the loading of CNS. However, too porous structure compromised the mechanical properties, such that CNS2.3 was the best from a comprehensive consideration including the pore structure and mechanical properties. As a result, CNS2.3 showed not only 2 times higher water permeability than CNS0 but also 5 times longer operation duration until membrane cleaning was required.

• Korean Journal of Remote Sensing
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• v.36 no.5_2
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• pp.867-879
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• 2020

As the era of space technology utilization is approaching, the launch of CAS (Compact Advanced Satellite) 500-1/2 satellites is scheduled during 2021 for acquisition of high-resolution images. Accordingly, the increase of image usability and processing efficiency has been emphasized as key design concepts of the CAS 500-1/2 ground station. In this regard, "CAS 500-1/2 Image Acquisition and Utilization Technology Development" project has been carried out to develop core technologies and processing systems for CAS 500-1/2 data collecting, processing, managing and distributing. In this paper, we introduce the results of the above project. We developed an operation system to generate precision images automatically with GCP (Ground Control Point) chip DB (Database) and DEM (Digital Elevation Model) DB over the entire Korean peninsula. We also developed the system to produce ortho-rectified images indexed to 1:5,000 map grids, and hence set a foundation for ARD (Analysis Ready Data)system. In addition, we linked various application software to the operation system and systematically produce mosaic images, DSM (Digital Surface Model)/DTM (Digital Terrain Model), spatial feature thematic map, and change detection thematic map. The major contribution of the developed system and technologies includes that precision images are to be automatically generated using GCP chip DB for the first time in Korea and the various utilization product technologies incorporated into the operation system of a satellite ground station. The developed operation system has been installed on Korea Land Observation Satellite Information Center of the NGII (National Geographic Information Institute). We expect the system to contribute greatly to the center's work and provide a standard for future ground station systems of earth observation satellites.

• Journal of Distribution Research
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• v.17 no.1
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• pp.37-63
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• 2012

In franchise business, exclusive sales territory (sometimes EST in table) protection is a very important issue from an economic, social and political point of view. It affects the growth and survival of both franchisor and franchisee and often raises issues of social and political conflicts. When franchisee is not familiar with related laws and regulations, franchisor has high chance to utilize it. Exclusive sales territory protection by the manufacturer and distributors (wholesalers or retailers) means sales area restriction by which only certain distributors have right to sell products or services. The distributor, who has been granted exclusive sales territories, can protect its own territory, whereas he may be prohibited from entering in other regions. Even though exclusive sales territory is a quite critical problem in franchise business, there is not much rigorous research about the reason, results, evaluation, and future direction based on empirical data. This paper tries to address this problem not only from logical and nomological validity, but from empirical validation. While we purse an empirical analysis, we take into account the difficulties of real data collection and statistical analysis techniques. We use a set of disclosure document data collected by Korea Fair Trade Commission, instead of conventional survey method which is usually criticized for its measurement error. Existing theories about exclusive sales territory can be summarized into two groups as shown in the table below. The first one is about the effectiveness of exclusive sales territory from both franchisor and franchisee point of view. In fact, output of exclusive sales territory can be positive for franchisors but negative for franchisees. Also, it can be positive in terms of sales but negative in terms of profit. Therefore, variables and viewpoints should be set properly. The other one is about the motive or reason why exclusive sales territory is protected. The reasons can be classified into four groups - industry characteristics, franchise systems characteristics, capability to maintain exclusive sales territory, and strategic decision. Within four groups of reasons, there are more specific variables and theories as below. Based on these theories, we develop nine hypotheses which are briefly shown in the last table below with the results. In order to validate the hypothesis, data is collected from government (FTC) homepage which is open source. The sample consists of 1,896 franchisors and it contains about three year operation data, from 2006 to 2008. Within the samples, 627 have exclusive sales territory protection policy and the one with exclusive sales territory policy is not evenly distributed over 19 representative industries. Additional data are also collected from another government agency homepage, like Statistics Korea. Also, we combine data from various secondary sources to create meaningful variables as shown in the table below. All variables are dichotomized by mean or median split if they are not inherently dichotomized by its definition, since each hypothesis is composed by multiple variables and there is no solid statistical technique to incorporate all these conditions to test the hypotheses. This paper uses a simple chi-square test because hypotheses and theories are built upon quite specific conditions such as industry type, economic condition, company history and various strategic purposes. It is almost impossible to find all those samples to satisfy them and it can't be manipulated in experimental settings. However, more advanced statistical techniques are very good on clean data without exogenous variables, but not good with real complex data. The chi-square test is applied in a way that samples are grouped into four with two criteria, whether they use exclusive sales territory protection or not, and whether they satisfy conditions of each hypothesis. So the proportion of sample franchisors which satisfy conditions and protect exclusive sales territory, does significantly exceed the proportion of samples that satisfy condition and do not protect. In fact, chi-square test is equivalent with the Poisson regression which allows more flexible application. As results, only three hypotheses are accepted. When attitude toward the risk is high so loyalty fee is determined according to sales performance, EST protection makes poor results as expected. And when franchisor protects EST in order to recruit franchisee easily, EST protection makes better results. Also, when EST protection is to improve the efficiency of franchise system as a whole, it shows better performances. High efficiency is achieved as EST prohibits the free riding of franchisee who exploits other's marketing efforts, and it encourages proper investments and distributes franchisee into multiple regions evenly. Other hypotheses are not supported in the results of significance testing. Exclusive sales territory should be protected from proper motives and administered for mutual benefits. Legal restrictions driven by the government agency like FTC could be misused and cause mis-understandings. So there need more careful monitoring on real practices and more rigorous studies by both academicians and practitioners.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.27-35
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• 2005

This study was performed to determine the effect of three different concentrations of soy-isoflavones on excretions through urine and feces in either sham-operated or ovariectomized female rats. Seventy-two 16-week old Sprague-Dawley rats underwent sham operation or bilateral ovariectomy. They were provided diets containing different levels of soy isoflavones for 6 weeks: 50 ppm (low isoflavone intake; LI), 250 ppm (medium isoflavone intake; MI) and 500 ppm (high isoflavone intake; HI). The subsequent fecal and urinary excretions of daidzein and genistein were then measured. In the sham operated rats, body weight gains and food efficiency ratio of the MI and HI groups were significantly lower than control group, while food intake was not different. However, there was no significant difference in ovariectomized rats. The fecal excretion of daidzein was significantly higher in the HI group than the LI and MI groups, and that of genistein increased as dietary isoflavone intakes increased in both the sham operation and ovariectomy. The reverse tendency of fecal recovery was shown with dietary isoflavone dose only in genistein among ovariectomized rats. When dietary isoflavones were increased from 50 ppm to 500 ppm, the amounts of daidzein and genistein in the urine increased dose-dependently. The higher intakes of isoflavones leaded to lower recovery rates of daidzein and genistein in the urine in the sham-operated rats but not in the ovariectomized rats. The urinary recovery was significantly higher in the LI group than the MI and HI groups in the sham-operated rats. The excreted amounts and recovery of the two isoflavones in the urine were higher in the sham operated groups than in the ovariectomized groups, which implied an increased bioavailability of isoflavones by ovariectomy. Therefore, the results suggest that a more efficient use of soy isoflavones in ovariectomized conditions may occur, which indicates that a higher dose of soy isoflavones is necessary for the postmenopausal states.

• Women's Health Nursing
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• v.6 no.2
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• pp.234-257
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• 2000

At present in the medical care, the study and effort for producing health service to consider efficiency, effectiveness, and quality are urgently called for because of the difficulty in the keen competition according to the inter- nationalization and opening, the operation in the medical institution service testing system, the change in the medical policy of KDRGs, and the lack of the health care cost increasing rate. As an alternative, the case management for the new management system is introduced in the U.S., and the Critical Pathway that is the method designing the contents of activity and its result has been developed and applied in order to anticipate and manage the patient-outcome for the realization of the cost-effective case-management. Thus, this study intended to analyze the effectiveness to obtain by developing the Critical Pathway presented as the method to improve the quality-betterment and cost effectiveness through the continuous and consistent patient management for the hysterectomy patient and applying it to the real practice. As a study method, this author formed a conceptual framework through considering five Critical Pathway used in the current U.S. and three Critical Pathway presented in the literature to develop the Critical Pathway for the hysterectomy patient, and made out the preliminary Critical Pathway through reviewing the old chart. This author made the verified the validity of the expert group about the developed Critical Pathway, and to confirm the possibility of practice application, completed and settled the final Critical Pathway after using the Critical Pathway to the hysterectomy patient from March 1st to 15th, 1997. Finally, to analyze the application-effect of the developed Critical Pathway, this author offered health care service applying the Critical Pathway to the hysterectomy patient from April 15th to August 31th, 1997. The guide for the Critical Pathway was carried out in advance by outpatient setting nurse for outpatient setting visit before the operation, and after hospitalization the primary nurse monitored the execution degree on the every duty. After discharge this author surveyed the complication through phone visiting, and one month after discharge surveyed the patient's reaction about the offered service when outpatient setting visit and analyzed the result. The source for health care cost was obtained by the statistics about the hospital charge which was offered by the General Business Department. The results were as follows. 1. It was decided that the vertical line of the Critical Pathway was made up of eight items such as monitoring/assessment, treatment, line/drains, activity, medication, lab test, diet, patient teaching, and the horizontal line of the Critical Pathway was made up of from hospitalization to discharge. 2. After the analysis of service contents through reviewing the old chart, it was decided that the horizontal line of the preliminary Critical Pathway was made up of from hopitalization to fourth postoperative day, and the vertical line of it was divided into eight items which were the contents to occur with the time frame of the horizontal line. 3. After the verifying the validity of the expert group about the preliminary Critical Pathway, the horizontal line was amended from hopitalization to third postoperative day, and taking their consensus, some contents of the horizontal line was amended and deleted. 4. From March 1st to 15th, 1997, to confirm the clinical suitability, this author offered eight hysterectomy patients the medical service through the Critical Pathway. The result was that three of them could be discharged at the expected discharge day, and the others later than that day. Supplementing the preliminary Critical Pathway through analyzing the cause of that delay- case, this author developed the final Critical Pathway. 5. There were no significant differences between the experimental and the control group in the incidence of complication(P > 0.05). 6. The 92.4% of experimental group was satisfied with the Critical Pathway service. 7. The length of hospital stay of the experimental group offered with the Critical Pathway service was 4.6 days and there was a significant difference that it was 1.3 days shorter than that of the control group(t=-29.514, P=0.000). 8. There wsa a significant difference that the mean medical charge per one patient of the experimental group offered the Critical Pathway service was cheaper \124,150 than that of the control group(t=-9.826, P=0.000). 9. The result that the author assumed and analyzed hospital income with the rate of turning bed was assumed that the increase of hospital income was \63,245,072 for that study, and the income increase was expected with \68,704,864 for a year. The result that this author applied the Critical Pathway to the hysterectomy patient have no differences in the incidence of complication, high satisfaction with that service, and the length of hospital stay decreased in the experimental group, and the mean hospital charge per one patient decreased, but hospital income increased. Suggestions for further study and nursing practice are as follows. 1. The study to apply the Critical Pathway for a year, verify the validity, and measure the effect repeatedly is needed. 2. To apply and manage the Critical Pathway effectively, the study to computerize it is needed. 3. The study to develop hospital-based Critical Pathway about other diseases or procedure, and measure the effect is needed.

• KSBB Journal
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• v.14 no.3
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• pp.328-336
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• 1999

A green microalga, Chlorella vulgaris UTX 259, was cultivated in a bench-scale raceway pond. During the culture, 15%(v/v) $CO_2$ was supplied and industrial wastewater discharged from a steel-making plant was used as a culture medium. In a small scale culture bottle, the microalga grew up to 1.8 g $dm^{-3}$ of cell concentration and ammonia was completely removed from the wastewater with an yield coefficient of 25.7 g dry cell weight $g^{-1}\;NH_3-N$. During the bottle-culture, microalga was dominant over heterotrophic microorganisms in the culture medium. Therefore, the amount of carbon dioxide fixation could be estimated from the change of dry cell weight. In a semi-continuous operation of raceway pond with intermittent lighting (12 h light and 12 h dark), increase of dilution rate resulted in increase of the ammonia removal rate as well as the $CO_2$ fixation rate but the ammonia removal efficiency decreased. Ammonia was not completely removed from the medium (wastewater) of raceway pond which was operated in a batch mode under a light intensity up to 20 klux. The incomplete removal of ammonia was believed due to insufficient light supply. A mathematical model, capable of predicting experimental data, was developed in order to simulate the performance of the raceway pond under the light intensity of sun during a bright daytime. Simulation results showed that the rates of $CO_2$ fixation and ammonia removal could be enhanced by increasing light intensity. According to the simulation, 80 mg $dm^{-3}$ of ammonia in the medium could be completely removed if the light intensity was over 60 klux with a continuous lighting. Under the optimal operating condition determined by the simulation, the rates of carbon dioxide fixation and ammonia removal in the outdoor operation of raceway pond were estimated as high as $24.7 g m^{-2} day^{-1}$ and $0.52 g NH_3-N m^{-2} day^{-1}$, respectively.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1243-1254
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• 2021

For water resources operation or agricultural water management, it is important to accurately predict evapotranspiration for a long-term future over a seasonal or monthly basis. In this study, reference evapotranspiration forecast (up to 12 months in advance) was performed using statistically predicted monthly temperatures and temperature-based Hamon method for the Han River basin. First, the daily maximum and minimum temperature data for 15 meterological stations in the basin were derived by spatial-temporal downscaling the monthly temperature forecasts. The results of goodness-of-fit test for the downscaled temperature data at each site showed that the percent bias (PBIAS) ranged from 1.3 to 6.9%, the ratio of the root mean square error to the standard deviation of the observations (RSR) ranged from 0.22 to 0.27, the Nash-Sutcliffe efficiency (NSE) ranged from 0.93 to 0.95, and the Pearson correlation coefficient (r) ranged from 0.97 to 0.98 for the monthly average daily maximum temperature. And for the monthly average daily minimum temperature, PBIAS was 7.8 to 44.7%, RSR was 0.21 to 0.25, NSE was 0.94 to 0.96, and r was 0.98 to 0.99. The difference by site was not large, and the downscaled results were similar to the observations. In the results of comparing the forecasted reference evapotranspiration calculated using the downscaled data with the observed values for the entire region, PBIAS was 2.2 to 5.4%, RSR was 0.21 to 0.28, NSE was 0.92 to 0.96, and r was 0.96 to 0.98, indicating a very high fit. Due to the characteristics of the statistical models and uncertainty in the downscaling process, the predicted reference evapotranspiration may slightly deviate from the observed value in some periods when temperatures completely different from the past are observed. However, considering that it is a forecast result for the future period, it will be sufficiently useful as information for the evaluation or operation of water resources in the future.

• The KIPS Transactions:PartA
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• v.11A no.1
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• pp.49-56
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• 2004

The performance of the multiprocessor systems is limited by the several factors. The system performance is affected by the processor speed, memory delay, and interconnection network bandwidth/latency. By the evolution of semiconductor technology, off the shelf microprocessor speed breaks beyond GHz, and the processors can be scalable up to multiprocessor system by connecting through the interconnection networks. In this situation, the system performances are bound by the latencies and the bandwidth of the interconnection networks. SCI, Myrinet, and Gigabit Ethernet are widely adopted as a high-speed interconnection network links for the high performance cluster systems. Performance improvement of the interconnection network can be achieved by the bandwidth extension and the latency minimization. Speed up of the operation clock speed is a simple way to accomplish the bandwidth and latency betterment, while its physical distance makes the difficulties to attain the high frequency clock. Hence the system performance and scalability suffered from the interconnection network limitation. Duplicating the link of the interconnection network is one of the solutions to resolve the bottleneck of the scalable systems. Dual-ring SCI link structure is an example of the interconnection network improvement. In this paper, I propose a network topology and a transaction path algorism, which optimize the latency and the efficiency under the duplicated links. By the simulation results, the proposed structure shows 1.05 to 1.11 times better latency, and exhibits 1.42 to 2.1 times faster execution compared to the dual ring systems.