• KDI Journal of Economic Policy
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• v.13 no.4
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• pp.31-57
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• 1991

Korean firms of all sizes, from virtually every industry, have used and are using the term "excessive competition" to describe the state of their industry and to call for government interventions. Moreover, the Korean government has frequently responded to such calls in various ways favorable to the firms, such as controlling entry, curbing capacity investments, or allowing collusion. Despite such interventions' impact on the overall efficiency on the Korean economy as well as on the wealth distribution among diverse groups of economic agents, the term "excessive competition", the basis for the interventions, has so far escaped rigorous scrutiny. The objective of this paper is to clarify the notion of "excessive competition" and "over-investment" which usually accompanies "excessive competition", and to examine the circumstances under which they might occur. We first survey the cases where the terms are most widely used and proceed to examine those cases to determine if competition is indeed excessive, and if so, what causes "excessive competition". Our main concern deals with the case in which the firms must make investment decisions that involve large sunk costs while facing uncertain demand. In order to analyze this case, we developed a two period model of capacity precommitment and the ensuing competition. In the first period, oligopolistic firms make capacity investments that are irreversible. Demand is uncertain in period 1 and only the distribution is known. Thus, firms must make investment decisions under uncertainty. In the second period, demand is realized, and the firms compete with quantity under realized demand and capacity constraints. In the above setting, we find that there is "no over-investment," en ante, and there is "no excessive competition," ex post. As measured by the information available in period 1, expected return from investment of a firm is non-negative, overall industry capacity does not exceed the socially optimal level, and competition in the second period yields an outcome that gives each operating firm a non-negative second period profit. Thus, neither "excessive competition" nor "over-investment" is possible. This result will generally hold true if there is no externality and if the industry is not a natural monopoly. We also extend this result by examining a model in which the government is an active participant in the game with a well defined preference. Analysis of this model shows that over-investment arises if the government cannot credibly precommit itself to non-intervention when ex post idle capacity occurs, due to socio-political reasons. Firms invest in capacities that exceed socially optimal levels in this case because they correctly expect that the government will find it optimal for itself to intervene once over-investment and ensuing financial problems for the firms occur. Such planned over-investment and ensuing government intervention are the generic problems under the current system. These problems are expected to be repeated in many industries in years to come, causing a significant loss of welfare in the long run. As a remedy to this problem, we recommend a non-intervention policy by the government which creates and utilizes uncertainty. Based upon an argument which is essentially the same as that of Kreps and Wilson in the context of a chain-store game, we show that maintaining a consistent non-intervention policy will deter a planned over-investment by firms in the long run. We believe that the results obtained in this paper has a direct bearing on the public policies relating to many industries including the petrochemical industry that is currently in the center of heated debates.

• Korea Journal of Hospital Management
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• v.2 no.1
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• pp.1-21
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• 1997

In order to analyze the shifts in the volume and profits of Computed Tomography(CT) and Magnetic Resonance Imaging(MRI) utilization for a year before and after the implementation of insurance coverage for CT, this study has been undertaken examining CT and MRI cost data from 'Y' University Hospital situated in Seoul, Korea. Following are the results of this study: 1. The medical insurance payment for CT, implemented on January 1, 1996, increased CT utilization from January 1996 to April 1996 due to low insurance premiums: however, from May 1996 the number of CT cases significantly decreased as a result of strengthened medical cost reviews and the new 'Detailed standards for approval of CT' announced near the end of April 1996 by the insurer. 2. Since the implementation of insurance coverage for CT, CT fee reduction rates for reimbursements by the insurer to the hospital were 50% and 40% for January and February, respectively, and 31% and 15% for March and April. A significant point in the lowering of the reduction rate was reached in May at 11%; furthermore, since June the reduction rate fell below the average reduction rate for reimbursements for all procedures. If the 'Detailed standards for approval of CT' had been announced before the implementation of insurance coverage for CT, CT utilization would not have been so high due to the need to meet those 'standards'. In addition, loss of hospital profits resulting from the reduction for reimbursements would not have occurred. 3. The shifts in MRI utilization showed that there was no particular change with the beginning of insurance coverage for CT, and the introduction of the 'Detailed standards for approval of CT' made MRI utilization increase because MRI is free of restrictions imposed by the insurer. 4. The relationship between CT utilization and MRI utilization showed that they were supplementary to each other before insurance coverage for CT, but that CT was substituted for MRI because of strengthened medical cost reviews after t~e beginning of insurance coverage for CT. 5. The shifts in volume by patient characteristics showed that the number of inappropriate case patients, according to the insurer's "Standards for approval", decreased more than the number of appropriate case patients after the introduction of insurance coverage for CT. Therefore, the health insurance fee schemes for CT have influenced patient care. 6. The shifts in profits from CT utilization showed a net profit decrease of 31.6%. In order to match the pre-coverage profit level, 5,471 more cases would need to be seen and productivity would need to be increased by 32.7%. This profit decrease resulted from a decrease of CT utilization and low reimbursements. With insurance coverage, net profits from CT were 24.4%, and a margin of safety ratio was 39.6%. Because of the net profits and margin of safety ratio, CT utilization fees for insured appropriate cases could not be considered inappropriate. 7. The shifts in profits from MRI utilization before and after the introduction of CT coverage showed that in order to match pre-CT coverage profit levels, 2,011 more cases would need to be seen and productivity would need to be increased by 9.2%. The reasons for needing to increase the number of cases and productivity result from cost burdens created by adding new MRI units. But with CT coverage already begun, MRI utilization increased. Combined with a minor increase in the MRI fee schedule, MRI utilization showed a net profit increase of 18.5%. Net profits of 62.8% and a 'margin of safety ratio' of 43.1% for MRI utilization showed that the hospital relied on this non-covered procedure for profits. 8. The shifts in profits from CT and MRI utilization showed the net profits from CT decreased by 2.33billion Won while the net profits from MRI increased by 815.7million Won. Overall, these two together showed a net profit decrease of 1.51billion Won. The shifts in utilization showed a functional substitutionary relationship, but the shifts in profits did not show a substitutionary relationship. From these results, We can conclude that if insurance is to be expanded to include previously uncovered procedures using expensive medical equipment, detailed standards should be prepared in advance. The decrease in profits from the shifts in coverage and changes in fees is a difficult burden that should be shared, not carried by the hospital alone. Also, a new or improved fee schedule system should include revised standards between items listed and the appropriateness of the fee schedule should constantly be ensured. This study focused on one university hospital in Seoul and is therefore limited in general applicability. But it is valuable for considering current issues and problems, such as the influence of CT coverage on hospital management. Future studies will hopefully expand the scope of the issues considered here.

• Clinical and Experimental Pediatrics
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• v.46 no.10
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• pp.966-971
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• 2003

Purpose : It is now well established that infection and inflammation play an important role in the pathogenesis of ischemic brain damage. The loss of neutrophils from systemic circulation is an associated finding in injury mediated by granulocyte. Periventricular leukomalacia(PVL) caused by ischemia is the principal form of brain injury in premature infants. This study was conducted to evaluate whether the low neutrophil count is associated with periventricular leukomalacia(PVL) in premature infants. Methods : Retrospective review of medical records was undertaken. Subjects were premature infants with a birth weight of less than 1,500 gm, admitted to the Neonatal Intensive Care Unit of Kyungpook University Hospital. A complete blood count of peripheral blood was done within the 1st hour of life. Neutropenia was defined as absolute neutrophil count < $1,500/mm^3$, PVL as increased periventricular echodensities followed by cyst formation on ultrasonography or corresponding signs on brain MRI. Results : Thirteen infants out of a total population of 37 revealed neutropenia. Respiratory distress syndrome and requirement for respiratory support were not different between infants with neutropenia( neutropenia group) and infants without neutropenia(control group). Intraventricular hemorrhage (IVH) and grade 3 and 4 IVH were more frequent in neutropenia group(P<0.05). There was no statistically significant increase of PVL in neutropenia group. The neutrophil count was $18,760.0{\pm}10,266.1/mm^3$, $7,272.0{\pm}7,435.0/mm^3$ infants with PVL and $11,131.7{\pm}3,386.5/mm^3$, $2,407.5{\pm}1,933.1/mm^3$ in infants without PVL, respectively. The frequency of mechanical ventilation and artificial surfactant therapy was higher in infants with PVL compared with infants without PVL, but statistical analysis was not performed due to small number of subjects. Conclusion : A low number of neutrophils in the systemic circulation was not associated with an increased risk of PVL in premature infants.

• Korean Journal of Psychosomatic Medicine
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• v.27 no.2
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• pp.138-146
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• 2019

Objectives : This study examined the association between depression and survival time in terminal cancer patients admitted to the palliative care unit. Emotional problems are important for terminal cancer patients in the palliative care unit, and evaluation of patients' depression plays an important role in treatment planning. Methods : From October 2015 to August 2018, we conducted a retrospective study of 291 terminal cancer patients admitted to a palliative care unit at a university hospital and evaluated depression with PHQ-9 at admission. Of the 291 patients, 146 (50.2%) completed PHQ-9 but 145 (49.8%) were not evaluated due to loss of consciousness or rejection. Results : 4-week survival rate in the Kaplan-Meier survival analysis were 45.4% in the non-depressed group (PHQ-9<10) and 18.7% in the depressed group (PHQ-9≥10). According to the severity of depression, in the Cox proportional hazard model, the risk of mortality in moderate, moderately sever and severe group was 2.778, 1.882 and 3.423 times higher than minimal group, respectively. Conclusions : Of the patients with terminal cancer who were admitted to the palliative care unit, the survival time was shorter in the depressed group than in the non-depressed group. Further research is needed to determine if treatment of depression increase the survival in terminal cancer patients.

• Economic and Environmental Geology
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• v.36 no.5
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• pp.375-380
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• 2003

This study was carried out 1) to investigate the pH effect on solubilization of phenanthrene by biosurfactant in aqueous system and 2) to evaluate the pH effect on the biodegradation rate of phenanthrene in the presence and the absence of the biosurfactant by phenanthrene degraders. Tween 80, which is a chemically synthesized surfactant, showed greater solubilizing capacity than rhamnolipid. The solubilization capacity can be expressed as a MSR(molar solubilization ratio=moles of organic compounds solubilized per mole of surfactant). The calculated MSR of Tween 80 and rhamnolipid were 0.1449 and 0.0425 respectively. The kinetic study of phenanthrene solubilization by rhamnolipid showed that solubilization mechanism could reach equilibrium within 24 hours. Addition of 240 ppm rhamnolipid solution, which concentration is 4.3 times of Critical Micelle Concentration(CMC), caused 9 times solubility enhancement compared to water solubility. The highest solubilities were detected around a pH range of 4.5-5.5. Changes in apparent solubility with the changes in pH are possibly related to the fact that the rhamnolipid, an anionic surfactant, can form different structures depending on the pH. Two biodegradation experiments were performed in the absence and the presence of rhamnolipid, with the cell growth investigated using a spread plate method. The specific growth rates at pH 6 and 7 were higher than at the other pH, and the HPLC analysis data, for the total phenanthrene loss, confirmed the trends in the $\mu$(specific growth rate) values. In presence of rhamnolipid, maximum $\mu$ values shifted from around pH 5 which showed maximum enhancement of solubility in the abiotic experiment, compared to the $\mu$ values obtained without the biosurfactant. In this study, the increase in the observed specific grow rate(1.44 times) was not as high as the increase in solubilization(5 times). This was supported by the fact all the solubilized phenanthrene is not bioavailable to microorganisms.

• Radiation Oncology Journal
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• v.14 no.4
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• pp.291-297
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• 1996

Purpose : This study was performed to evaluate survival, failure patterns, and prognostic factors of MMR patients after radiation therapy. We also discussed the need for chemotherapy. Materials and Methods : A retrospective analysis was done for 23 patients with MMR who were treated with radiation therapy from June 1985 to November 1992. There were 19 male and 4 female patients, The patients' age ranged from 17 to 71 years (median 39 years). Systemic symptoms including fever, weight loss, or malaise were found in $30\%$ of the patients. The nasal cavity was most frequently involved No patients had nodal involvement at diagnosis. There were 2 patients with distant metastasis at presentation. Radiation therapy was delivered five times a week, 1.8 Gy daily, total $45\~54$ Gy (median 50.4 Gy) using 6 MV X-ray No patients received chemotherapy as initial treatment. Results : Overall 5-year and 10-year survival rates were $52.4\%$ and $44.1\%$, respectively. Seventy Percent(12/17) of the patients achieved complete response to radiotherapy, and $29.4\%$ (5/17) achieved partial response. The Patients with complete response showed a better 5-year survival rate than those with partial response ($66.9\%$ vs. $20\%$. p=0.004). Symptom duration before diagnosis, the presence of systemic symptom, and the number of primary sites had no influence on survival. The patterns of failure were as follows: local failure(1), failure in adjacent site(1), local and distant failure(1) distant metastasis(2). and conversion to malignant lymphoma(1). We could not find factors associated with the patterns of failure. Conclusion : The most important facto associated with survival was the response to radiotherapy. Seventeen percent of the patients had distant metastasis, and the salvage after distant metastasis was not successful. However. about $50\%$ of the patients could achieve long-term survival with local radiation therapy alone. Therefore, chemotherapy of MMR should be done after a prospective randomized study for the factors associated with distant metastasis.

• Radiation Oncology Journal
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• v.26 no.1
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• pp.1-9
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• 2008

Purpose: To evaluate the impact of postoperative radiotherapy on loco-regional failure in patients with vulvar carcinoma and to determine the treatment strategy for inguinal lymph nodes. Materials and Methods: Sixty-six patients who received treatment for primary vulvar carcinoma at Seoul National University Hospital, from October 1979 through June 2004, were retrospectively analyzed. Sixteen patients were excluded from the analysis due to the following reasons: distant metastases in two patients; palliative intent for six patients; previous radiotherapy given to the pelvis in three patients; follow-up loss after surgery for four patient; insufficient medical records for one patient. Of 50 eligible patients, 35 were treated with surgery alone(S), ten were treated with surgery followed by radiotherapy(S+RT), and five were treated with radiotherapy alone. Results: The 5-year overall survival(OS) and disease-free survival(DFS) rates of all patients were 91% and 78%, respectively. Twelve patients(26%) experienced treatment failures and the sites of initial failure were as follows: a primary site in eight patients; regional lymph nodes in three patients; the lung in one patient. Although risk factors for failure were more common in the S+RT group than the S group of patients(p<0.05), the DFS rates were similar for the two groups(5-year DFS rates, 78% vs. 83%, p=0.66). The incidences of occult lymph node metastases was 10%. Ten of 31 patients with clinically negative lymph nodes did not received inguinal lymph node dissection, but no patient experienced regional failure. Conclusion: Postoperative radiotherapy may have a potential benefit for patients with risk factors for failure. The omission of inguinal dissection or elective radiotherapy to the inguinal lymph nodes may be considered in low-risk patients with clinically negative lymph nodes.

• Journal of Veterinary Clinics
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• v.26 no.2
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• pp.138-143
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• 2009

Ischemia/reperfusion injury(I/RI) is the major cause of acute renal failure and delayed graft function(DGF) unavoidable in renal transplantation. Enormous studies on ischemia damage playing a role in activating graft rejection factors, such as T cells or macrophages, are being reported. Present study was performed to determine whether ischemia time would play an important role in activating rejection-related factors or not in rat models of I/RI. Male Sprague-Dawley rats were submitted to 30, 45, and 60 minutes of warm renal ischemia with nephrectomy or control animals underwent sham operation(unilateral nephrectomy). Renal function and survival rates were evaluated on day 0, 1, 2, 3, 5 and 7. Immunofluorescence staining of dendritic cells(DCs), natural killer(NK) cells, macrophages, B cells, CD4+ and CD8+ T cells were measured on day 1 and 7 after renal I/RI. Survival rates dropped below 50% after day 3 in 45 minutes ischemia. Histologic analysis of ischemic kidneys revealed a significant loss of tubular architecture and infiltration of inflammatory cells. DCs, NK cells, macrophages, CD4+ and CD8+ T cells were infiltrated from a day after I/RI depending on ischemia time. Antigen presenting cells(DCs, NK cells or macrophages) and even T cells were infiltrated 24 hours post-I/RI, which is at the time of acute tubular necrosis. During the regeneration phase, not only these cells increased but B cells also appeared in more than 45 minutes ischemia. The numbers of the innate and the adaptive immune cells increased depending on ischemia as well as reperfusion time. These changes of infiltrating cells resulting from each I/RI model show that ischemic time plays a role in activating rejection related immune factors and have consequences on progression of renal disease in transplanted and native kidneys.

• Food Science of Animal Resources
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• v.32 no.6
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• pp.842-848
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• 2012

This study was performed to investigate the physicochemical properties and tenderness of Hanwoo loin and round cuts, as affected by various raising periods and marbling scores. Five loin and round cuts with various marbling scores (5-9) from Hanwoo at various raising periods (27, 33, 30 mon) were collected. pH, Hunter color values (L, a, b), chemical composition, cooking loss, vacuum purge, and Warner-Bratzler shear values were evaluated according to two-way analysis of variance. No differences in pH values of Hanwoo loin were observed by raising period and marbling scores (p>0.05), but those of Hanwoo round at 27 mon was the lowest. Increased Hunter color values were observed with the increased marbling score and those at 27 and 30 mon were lower than 33 mon. Redness (a) and yellowness (b) of Hanwoo round cuts with the raising period of 27 mon were higher than those at 30 and 33 mon. The raising period of 27 mon showed higher water holding capacity than those of 30 and 33 mon, regardless of Hanwoo cut. Increased shear values (kgf) of Hanwoo round cuts were observed with increasing raising period (p<0.05). Increased marbling score decreased shear values in loin cuts, but no differences were observed in the round cuts. Based on these results, the parameters measured varied with meat cut, and raising period affected round pH, color, chemical composition, vacuum purge, and shear values. Marbling score affected color, chemical composition, water binding capacity, and shear values in loin cuts (p<0.05), but didn't affect any parameters in round cuts (p>0.05).

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.255-269
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• 2005

This study was aimed to investigate genetic relationships, variables, and correlations between economic traits and metabolic materials in serum components according to bleeding periods and breeding locations for the castrated and not castrated Hanwoo cattle at National Livestock Research Institute. Analysis of variance for serum hormones and metabolic materials showed significant differences by breeding locations except for testosterone and globulin. Statistical differences for serum components were detected by birth year except for cortisol, total protein, globulin and creatinine, and by castration except for total protein and BUN. All the serum components were tended to have sire effects except for testosterone resulting in some degree of additive gene actions. Breeding locations showed statistical significances for carcass weight and back fat thickness, but not in carcass rate, KPH, live weight and transportation weight loss. Effects of breeding locations and castration were significant for all weight measurement periods except for 9 month and 6 month, respectively. A significant sire effect was observed in all weight measurements. Least squared means for concentration of serum components by breeding year, season and castration were not significant. High concentration of cortisol, creatinine and triglyceride and low concentration of IGF-1 and glucose were detected in castrated cattle. Concentration of testosterone with castrated cattle was $5.2\%$ corresponding to non castrated cattle. Estimation of heritabilities of serum components using a sire model with restricted maximum likelihood were ranged 0.07 to 0.58. High heritabilities were estimated for total protein, albumin, globulin, cortisol, creatinine and BUN were 0.53, 0.54, 0.42, 0.45, 0.58 and 0.54, respectively. Low heritabilities were estimated fur calcium, testosterone and IGF-1 for 0.07, 0.15 and 0.12, respectively. Heritabilities for carcass weight, back fat thickness, meat yield index, KPH, and IMF were estimated as 0.39, 0.45, 0.30 0.13, and 0.93. Heritabilities of weights on 18, 12, 9, 6, and 24 month were estimated as 0.78, 0.76, 0.62, 0.58 and 0.58. Estimated heritabilities for average daily gain on 6${\~}$2, 12${\~}$18, and 18${\~}$24 month were 0.80, 0.75 and 0.19, respectively.