• Tuberculosis and Respiratory Diseases
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• v.44 no.2
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• pp.290-297
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• 1997

Background : Despite remarkable progress of understanding the pathophysiology and therapy of bronchial asthma, asthma morbidity and mortality are on the rise. Also hospitalization and attending rates of emergency department for asthma have been increasing gradually. We analyzed clinical characteristics and prognosis of patients who visited emergency room due to asthma attack in order to define clinical characteristics of these group of patients. Method : We reviewed 105 adult asthmatic patients who attended emergency department of Korea University Hospital between August 1995 and July 1996, retrospectively. Results : 103 patients(56 female, 47 males, mean age : 48.6 years) attended-68 self referral, 18 practitioner referral and 17 OPD transfer- and 86 patients(83.5%) were admitted. Attending emergncy department was clearly more frequent in December(13.6%) and May(12.6%). Time lag between onset of asthmatic attack and arrival at the hospital was $14.2{\pm}15.5$ hour and initial peak expiratory flow rate was $166.7{\pm}68.3L/min$.(43.3% predicted) The commonest cause for visiting emergency room was aggravation of asthma due to upper respiratory tract infection in mild asthmatics. About half of them had history of previous ER visits. Their prognosis was not bad, but after discharge, about half of patients escaped from OPD follow-up. Conclusion : As a group they merit detailed attention and follow up arrangement. Clinician need to monitor and review the treatment plans, the medications, the patient's management technique, and the level of asthma control. For this group, plans for longer term treatment, including asthma education program and adjustment of overall treatment plan should be made.

• Tuberculosis and Respiratory Diseases
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• v.46 no.3
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• pp.317-326
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• 1999

Background: Neural control of airway function is through parasympathetic, sympathetic and non-adrenergic, non-cholinergic mechanisms. The autonomic nervous system controls the airway smooth muscle tone, mucociliary system, permeability and blood flow in the bronchial circulation and release of mediators from the mast cells and other inflammatory cells. The cardiovascular and respiratory autonomic efferent fibers have a common central origin, so altered cardiovascular autonomic reflexes could reflect the altered respiratory autonomic status. Therefore, we performed this study to assess the autonomic abnormality and determine the correlating factors of severity of autonomic neuropathy in patients with chronic obstructive pulmonary disease(COPD) using easily reproducible cardiovascular autonomic reflex function test. Method: The study included 20 patients with COPD and 20 healthy persons obtained on Health Promotion Center in Yeungnam university hospital. All the patients had history and clinical features of COPD as defined by the American Thoracic Society. Any patients with myocardial ischemia, cardiac arrythmia, hypertension, central or peripheral nervous system disease, diabetes mellitus, or any other diseases known to produce autonomic neuropathy, has excluded. The autonomic nervous system function tests included three tests evaluating the parasympathetic system and two tests evaluating the sympathetic system. And also all subjects were subjected to pulmonary function test and arterial blood gas analysis. Results: Autonomic dysfunction was more commonly associated with patients with COPD than healthy person The parasympathetic dysfunction was frequent in patient with COPD, but sympathetic dysfunction seemed preserved. The severity of parasympathetic dysfunction in patients with COPD was correlated with the degree of duration of disease, smoking, reductions in the value of $FEV_1$ and FVC, and arterial hypoxemia but no such correlation existed for age, type of COPD, $FEV_1$/FVC, or $PaCO_s$. Conclusion: There is high frequency of parasympathetic dysfunction associated with COPD and the parasympathetic abnormality in COPD is increased in proportion to severity of airway disease. In COPD, parasympathetic dysfunction probably does not the cause of disease, but it may be an effect of disease progression.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.2
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• pp.89-109
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• 1999

Vascular spasm which has been reported to occur in 25% of clinical cases continues to be a problem in microvascular surgery; When prolonged and not corrected, it can lead to low flow, thrombosis, and replant or free flap failure. Ischemia, intimal damage, acidosis and hypovolemia have been implicated as contributors to the vascular spasm. Although much work has been done on the etiology and prevention of vasospasm, a spasmolytic agent capable of firmly protecting against or reversing vasospasm has not been found. Therefore vascular freezing was introduced as a new safe method that immediately and permanently relieves the vasospasm and can be applied to microsurgical transfers. Cryosurgery can be defined as the deliberate destruction of diseased tissue or relief the vascular spasm in microvascular surgery by freezing in a controlled manner. 96 Sprague Dawley rats each weighing within 250g were used and divided into 2 group, experimental 1 and 2 group. In the experimental 1 group, right epigastric vessels (artery and vein) were freezed with a cryoprobe using $N_2O$ gas for 1 min. In the experimental 2 group, after freezing for 1 min, thawing for 30 secs and repeat freezing for 30 secs. Left side was chosen as control group in both group. We sacrified the experimental animals by 1 day, 3 days, 1 week, 2 weeks, 4 weeks & 5 months and observed the sequential change that occur during regeneration of epigastric vessels using a histologic, histomorphometric, immunohistochemical and SEM study after the vascular freezing. The results were as follows1. In epigastric arteries, internal diameters had statistically significant enlargement in 1 day, 3 days of Exp-1 group and 1 day, 3 days, 1 week & 2 weeks of Exp-2 group. Wall thickness had statistically significant thinning in 2 weeks of Exp-2 group. 2. In epigastric veins, internal diameters had enlargement of statistical significance in 1 day of Exp-1 and Exp-2 group. 3. The positive PCNA reactions in smooth muscle appeared in 1 week and increased until 2 weeks, decreased in 4 weeks. There was no statistical significance between Exp-1 and Exp-2 group. 4. The positive ${\alpha}$-SMA reaction in smooth muscles showed weak responses until 1 week and slowly increased in 2 weeks and showed almost control level in 4 weeks. 5. The positive S-100 reactions in the perivascular nerve bundles showed markedly decrease in 1 day, 3 days and increased after 1 week and showed almost control level in 4 weeks. Exp-1 group had stronger response than Exp-2 group. 6. In SEM, we observed defoliation of endothelial cell and flattening of vessel wall. Exp-2 group is more destroyed and healing was slower than Exp-1 group. To sum up, relief of vasospasm (vasodilatation) by freezing with cryoprobe was originated from the damage of smooth muscle layer and perivascular nerve bundle and the enlargement of internal diameter in vessels was similar to expeimental groups, but Exp-2 group had slower healing course and therefore vessel freezing in microsurgery can be clinically used, but repeat freezing time needs to be studied further.

• Journal of Intelligence and Information Systems
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• v.16 no.4
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• pp.131-145
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• 2010

The framework for making a coordinated decision for large-scale facilities has become an important issue in supply chain(SC) management research. The competitive business environment requires companies to continuously search for the ways to achieve high efficiency and lower operational costs. In the areas of production/distribution planning, many researchers and practitioners have developedand evaluated the deterministic models to coordinate important and interrelated logistic decisions such as capacity management, inventory allocation, and vehicle routing. They initially have investigated the various process of SC separately and later become more interested in such problems encompassing the whole SC system. The accurate quotation of ATP(Available-To-Promise) plays a very important role in enhancing customer satisfaction and fill rate maximization. The complexity for intelligent manufacturing system, which includes all the linkages among procurement, production, and distribution, makes the accurate quotation of ATP be a quite difficult job. In addition to, many researchers assumed ATP model with integer time. However, in industry practices, integer times are very rare and the model developed using integer times is therefore approximating the real system. Various alternative models for an ATP system with time lags have been developed and evaluated. In most cases, these models have assumed that the time lags are integer multiples of a unit time grid. However, integer time lags are very rare in practices, and therefore models developed using integer time lags only approximate real systems. The differences occurring by this approximation frequently result in significant accuracy degradations. To introduce the ATP model with time lags, we first introduce the dynamic production function. Hackman and Leachman's dynamic production function in initiated research directly related to the topic of this paper. They propose a modeling framework for a system with non-integer time lags and show how to apply the framework to a variety of systems including continues time series, manufacturing resource planning and critical path method. Their formulation requires no additional variables or constraints and is capable of representing real world systems more accurately. Previously, to cope with non-integer time lags, they usually model a concerned system either by rounding lags to the nearest integers or by subdividing the time grid to make the lags become integer multiples of the grid. But each approach has a critical weakness: the first approach underestimates, potentially leading to infeasibilities or overestimates lead times, potentially resulting in excessive work-inprocesses. The second approach drastically inflates the problem size. We consider an optimized ATP system with non-integer time lag in supply chain management. We focus on a worldwide headquarter, distribution centers, and manufacturing facilities are globally networked. We develop a mixed integer programming(MIP) model for ATP process, which has the definition of required data flow. The illustrative ATP module shows the proposed system is largely affected inSCM. The system we are concerned is composed of a multiple production facility with multiple products, multiple distribution centers and multiple customers. For the system, we consider an ATP scheduling and capacity allocationproblem. In this study, we proposed the model for the ATP system in SCM using the dynamic production function considering the non-integer time lags. The model is developed under the framework suitable for the non-integer lags and, therefore, is more accurate than the models we usually encounter. We developed intelligent ATP System for this model using genetic algorithm. We focus on a capacitated production planning and capacity allocation problem, develop a mixed integer programming model, and propose an efficient heuristic procedure using an evolutionary system to solve it efficiently. This method makes it possible for the population to reach the approximate solution easily. Moreover, we designed and utilized a representation scheme that allows the proposed models to represent real variables. The proposed regeneration procedures, which evaluate each infeasible chromosome, makes the solutions converge to the optimum quickly.

• Geophysics and Geophysical Exploration
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• v.21 no.3
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• pp.171-182
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• 2018

We performed the seismic field data processing using an open-source software (Madagascar) to verify if it is applicable to processing of field data, which has low signal-to-noise ratio and high uncertainties in velocities. The Madagascar, based on Python, is usually supposed to be better in the development of processing technologies due to its capabilities of multidimensional data analysis and reproducibility. However, this open-source software has not been widely used so far for field data processing because of complicated interfaces and data structure system. To verify the effectiveness of the Madagascar software on field data, we applied it to a typical seismic data processing flow including data loading, geometry build-up, F-K filter, predictive deconvolution, velocity analysis, normal moveout correction, stack, and migration. The field data for the test were acquired in Gunsan Basin, Yellow Sea using a streamer consisting of 480 channels and 4 arrays of air-guns. The results at all processing step are compared with those processed with Landmark's ProMAX (SeisSpace R5000) which is a commercial processing software. Madagascar shows relatively high efficiencies in data IO and management as well as reproducibility. Additionally, it shows quick and exact calculations in some automated procedures such as stacking velocity analysis. There were no remarkable differences in the results after applying the signal enhancement flows of both software. For the deeper part of the substructure image, however, the commercial software shows better results than the open-source software. This is simply because the commercial software has various flows for de-multiple and provides interactive processing environments for delicate processing works compared to Madagascar. Considering that many researchers around the world are developing various data processing algorithms for Madagascar, we can expect that the open-source software such as Madagascar can be widely used for commercial-level processing with the strength of expandability, cost effectiveness and reproducibility.

• Food Science and Preservation
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• v.23 no.5
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• pp.746-752
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• 2016

This research was carried out to identify aerodynamic property as a function of moisture content for designing equipment such as for post-harvest management. Terminal velocity of two wheat varieties {Backjjung (B) and Jogyeong (J)} with selected sound, damaged kernel and foreign materials (Wheat stick, Wheat husks) were measured with a designed vertical wind column at different moisture contents from about 9 to 30% wet basis. The results showed that terminal velocity of wheat and foreign materials except of Jogyeong's husks (p<0.05) had a significant difference at p<0.001. With increasing moisture content, the aerodynamic property values of the kernels and foreign materials of the two wheat varieties increased linearly. In detail, terminal velocity of sound and damaged kernel increased from 5.46 to 7.13 m/sec (B) and 7.48 to 8.60 m/sec (J), damaged kernel from 5.91 to 7.00 m/sec (B) and 6.48 to 7.75 m/sec (J). For foreign materials the terminal velocity of wheat stick increased from 2.92 to 4.07 m/sec (B) and 3.74 to 5.22 m/sec (J) whereas that of husks from 1.07 to 1.85 m/sec (B) and 2.02 to 2.33 m/sec (J) each. For air separation of wheat and foreign materials, the air flow should be less than 5.22 m/sec due to the range (1.07~5.22 m/sec) of foreign materials in wheat.

• Korean Journal of Ichthyology
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• v.21 no.1
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• pp.7-14
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• 2009

The effect of water temperature (T) and body weight (W) on oxygen consumption of fasted starry flounder Platichthys stellatus was investigated in order to assess the metabolic response of this species at given conditions. The oxygen consumption rate (OCR) was measured under six different water temperatures (4, 7, 10, 13, 16 and $19^{\circ}C$) and at two different body weights (mean weight of fry group : 1.5 g; fingerling group : 37.4 g) at an interval of 5 minutes for 24 hours using a continuous flow-through respirometer. In each treatment three replicates were set up and a total 540 fish in fry groups and 90 fish in fingerling groups were used. The OCRs increased with increase of water temperature in both groups (p<0.001). Mean OCRs at 4, 7, 10, 13, 16 and $19^{\circ}C$ were 1386.0, 1601.7, 1741.0, 1799.2, 2239.1 and $2520.3mg\;O_2\;kg\;fish^{-1}\;h^{-1}$ in fry groups, and 83.8, 111.4, 126.3, 147.1, 187.7 and $221.3mg\;O_2\;kg\;fish^{-1}\;h^{-1}$ in fingerling groups, respectively. The OCRs decreased with increasing body weights at six different water temperatures (p<0.001). The relationship between water temperature and body weight is described by the following equation : OCR=1520.91+40.85T-49.22W ($r^2=0.95$, p<0.001). The energy loss by metabolic response increased with an increase in water temperature and a decrease in body weight (p<0.001). Mean energy loss rates by oxygen consumption at 4, 7, 10, 13, 16 and $19^{\circ}C$ were 907.9, 1046.5, 1141.6, 1177.0, 1467.3 and $1650.1kJ\;kg\;fish^{-1}\;d^{-1}$ in fry groups and 54.8, 73.0, 82.9, 96.2, 122.9 and $144.6kJ\;kg\;fish^{-1}\;d^{-1}$ in fingerling groups, respectively. The $Q_{10}$ values of fingerling groups were higher than those of fry groups at given temperature ranges. The $Q_{10}$ values at $4{\sim}7^{\circ}C$, $7{\sim}10^{\circ}C$, $10{\sim}13^{\circ}C$, $13{\sim}16^{\circ}C$ and $16{\sim}19^{\circ}C$ were 1.62, 1.32, 1.12, 2.07 and 1.48 in fry groups, and 2.59, 1.52, 1.67, 2.25 and 1.73 in fingerling groups, respectively.

• Tuberculosis and Respiratory Diseases
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• v.54 no.5
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• pp.495-509
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• 2003

Background : Neutrophil-mediated inflammation is usually self-limiting, because neutrophils have a remarkably short life span. Prolonged neutrophil survival, which is caused by decreased spontaneous apoptosis, leads to persistent inflammation in sepsis. Because many inflammatory cytokines, which generate signals that delay apoptosis, are regulated by nuclear factor-${\kappa}B$ transcription factor, we hypothesized that nuclear factor-${\kappa}B$ might be related to the reduced neutrophil apoptosis observed in sepsis. Methods : Neutrophils of healthy volunteers and sepsis patients were freshly isolated from venous blood. Neutrophil apoptosis was assayed with two approaches : by counting apoptotic cells under a microscope and by flow cytometry using Annexin V. The activity of nuclear factor-${\kappa}B$ was assessed by immunofluorescent staining or electrophoretic mobility shift assay. Expression of X-linked inhibitor of apoptosis was measured by western blot assay. Results : We confirmed reduced spontaneous neutrophil apoptosis in patients with sepsis. The number of apoptotic neutrophils in patients with sepsis increased to the level of that in healthy controls after cycloheximide treatment, suggesting that decreased spontaneous neutrophil apoptosis is dependent on de novo protein synthesis. In patients with sepsis, basal neutrophil nuclear factor-${\kappa}B$ was activated compared to the level in healthy controls. Moreover, a blockade of nuclear factor-${\kappa}B$ activity reversed the decreased spontaneous neutrophil apoptosis in sepsis patients. Meanwhile, X-linked inhibition of apoptosis expression, which is regulated by nuclear factor-${\kappa}B$, decreased 24 hours after incubation in healthy persons, but persisted for 24 hours in patients with sepsis. Conclusion : These observations suggest that the reduced spontaneous neutrophil apoptosis observed in patients with sepsis may be related to the induction of survival protein by nuclear factor-${\kappa}B$.

• Journal of Korean Society of Forest Science
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• v.99 no.4
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• pp.559-567
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• 2010

This study was conducted to investigate the hydrological characteristics of groundwater level change and rainfall hydrological runoff processes caused by tunnel construction at Milbot bog located in Mt. Cheonseong. Data were collected from July 2004 to May 2008. The results were summarized as follows: The occurrence time of the direct runoff caused by unit rainfall at the Milbot bog were tended to be slower than those at general mountainous basin. Also, runoff did not sensitively respond to amount of rainfall at the most of the long and short term hydrograph. The annual runoff rates from 2004 to 2008 were 0.26, 0.13, 0.16, 0.25 and 0.27, respectively, slightly increased after 2005 regardless of the tunnel construction. Thus, the function of Milbot bog will be weakened, and it supposed to be changed to land in the future because of increasing annual runoff. The annual runoff rate for 4 years was 0.19, which is greatly lower than that of general mountainous basin. The recession coefficient of the direct runoff in short term hydrograph was ranged to 0.89~0.97, which is much larger than that of the general mountainous basin, 0.2~0.8. The recession coefficient of base flow ranged from 0.93 to 0.99, which are similar to general mountainous watershed's values. Groundwater level of Milbot bog increased or decreased in proportion to rainfall intensity, and in the descending time after the groundwater level was reached at peak point, it tends to be decreased very slowly. Also, groundwater level increased or decreased maintaining relatively high value after precedent rainfall. Groundwater level was highest during summer with heavy rainfall, but was lowest during winter. Average groundwater levels decreased annually from 2004 to 2008, -8.48 cm, -14.60 cm, -20.46 cm, -20.11 cm, -28.59 cm, respectively. Therefore, it seems that the Milbot bog is becoming dry and losing its function as a bog.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1634-1647
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• 2007

"To invest or not to invest?" Most business leaders are frequently faced with this question on new and ongoing projects. The challenge lies in deciding what projects to choose, expand, contract, defer, or abandon. The project valuation tools used in this process are vital to making the right decisions. Traditional tools such as discounted cash flow (DCF)/net present value (NPV) assume a "fixed" path ahead, but real world projects face uncertainties, forcing us to change the path often. Comparing to other traditional valuation methods, the real options approach captures the flexibility inherent to investment decisions. The use of real options has gained wide acceptance among practitioners in a number of several industries during the last few decades. Even though the options are present in all types of business decisions, it is still not considered as a proper method of valuation in some industries. Mining has been comparably slow to adopt new valuation techniques over the years. The reason fur this is not entirely clear. One possible reason is the level and types of risks in mining. Not only are these risks high, but they are also more numerous and involve natural risks compared with other industries. That is why the purpose of this study is to deal with a more practical approach to project valuation, known as real options analysis in mining industry. This paper provides a case study approach to the copper mining industry using a real options analysis. It shows how companies can minimize investment risks, exercise flexibility in decision making and maximize returns.