• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.1
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• pp.55-73
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• 2024

Unicorn companies are attracting attention around the world as they are recognized for their high corporate value in a short period of time as an innovative business models. Their growth process presents good lessons for the startup ecosystem and have a positive impact on national economic development and job creation. However, previous studies related to unicorn companies are focused on 'event studies' and 'case studies' such as characteristics of founders, environmental factors, business models and success/failure cases of companies already recognized as unicorns rather than a multifaceted approach. The occurrence of unicorn companies and Macroscopic analysis of related factors is lacking. Against this background, this study are considering the characteristics of unicorns examined through previous research and the current status unicorns with a high proportion of technology companies, the purpose was to analyze the impact of the country's technological competitiveness, such as 'technology human resource index', 'R&D index', and 'technology infrastructure index', on the increase in unicorn companies. For statistical analysis, data published by various international organizations, the Bank of Korea, and Statistics Korea from 2017 to 2020 and unicorn company data compiled by CB Insights were used as panel data for 44 countries to be tested by multiple regression analysis. As a result of the study, it was confirmed that the number of science majors had a positive (+) effect on the increase of unicorn companies in the case of technology human resource index, and in the case of R&D index, the total amount of R&D investment had a positive (+) effect on the increase of unicorn companies, while the number of Triad Patents Families and the number of scientific and technological papers published had a negative (-) effect on the increase of unicorn companies. Finally, in the case of technology infrastructure index, it was confirmed that the number of the world's 500th-ranked universities had a positive (+) effect on the increase of unicorn companies. This study is the first to reveal the causal relationship between national technological competitiveness and unicorn company growth based on country-specific and time-series empirical data, which were insufficiently covered in previous studies. and compared to the UN's ranking of the global industrial competitiveness index and the OECD's total R&D investment by country, Korea is considered to have technological and growth potential, while the number of unicorn companies driving growth as leaders of the innovative economy is relatively small, so the research results can be used when establishing policies to discover and foster unicorn companies in the future.

• Journal of Intelligence and Information Systems
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• v.27 no.3
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• pp.57-73
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• 2021

Maintenance and prevention of failure through anomaly detection of ICT infrastructure is becoming important. System monitoring data is multidimensional time series data. When we deal with multidimensional time series data, we have difficulty in considering both characteristics of multidimensional data and characteristics of time series data. When dealing with multidimensional data, correlation between variables should be considered. Existing methods such as probability and linear base, distance base, etc. are degraded due to limitations called the curse of dimensions. In addition, time series data is preprocessed by applying sliding window technique and time series decomposition for self-correlation analysis. These techniques are the cause of increasing the dimension of data, so it is necessary to supplement them. The anomaly detection field is an old research field, and statistical methods and regression analysis were used in the early days. Currently, there are active studies to apply machine learning and artificial neural network technology to this field. Statistically based methods are difficult to apply when data is non-homogeneous, and do not detect local outliers well. The regression analysis method compares the predictive value and the actual value after learning the regression formula based on the parametric statistics and it detects abnormality. Anomaly detection using regression analysis has the disadvantage that the performance is lowered when the model is not solid and the noise or outliers of the data are included. There is a restriction that learning data with noise or outliers should be used. The autoencoder using artificial neural networks is learned to output as similar as possible to input data. It has many advantages compared to existing probability and linear model, cluster analysis, and map learning. It can be applied to data that does not satisfy probability distribution or linear assumption. In addition, it is possible to learn non-mapping without label data for teaching. However, there is a limitation of local outlier identification of multidimensional data in anomaly detection, and there is a problem that the dimension of data is greatly increased due to the characteristics of time series data. In this study, we propose a CMAE (Conditional Multimodal Autoencoder) that enhances the performance of anomaly detection by considering local outliers and time series characteristics. First, we applied Multimodal Autoencoder (MAE) to improve the limitations of local outlier identification of multidimensional data. Multimodals are commonly used to learn different types of inputs, such as voice and image. The different modal shares the bottleneck effect of Autoencoder and it learns correlation. In addition, CAE (Conditional Autoencoder) was used to learn the characteristics of time series data effectively without increasing the dimension of data. In general, conditional input mainly uses category variables, but in this study, time was used as a condition to learn periodicity. The CMAE model proposed in this paper was verified by comparing with the Unimodal Autoencoder (UAE) and Multi-modal Autoencoder (MAE). The restoration performance of Autoencoder for 41 variables was confirmed in the proposed model and the comparison model. The restoration performance is different by variables, and the restoration is normally well operated because the loss value is small for Memory, Disk, and Network modals in all three Autoencoder models. The process modal did not show a significant difference in all three models, and the CPU modal showed excellent performance in CMAE. ROC curve was prepared for the evaluation of anomaly detection performance in the proposed model and the comparison model, and AUC, accuracy, precision, recall, and F1-score were compared. In all indicators, the performance was shown in the order of CMAE, MAE, and AE. Especially, the reproduction rate was 0.9828 for CMAE, which can be confirmed to detect almost most of the abnormalities. The accuracy of the model was also improved and 87.12%, and the F1-score was 0.8883, which is considered to be suitable for anomaly detection. In practical aspect, the proposed model has an additional advantage in addition to performance improvement. The use of techniques such as time series decomposition and sliding windows has the disadvantage of managing unnecessary procedures; and their dimensional increase can cause a decrease in the computational speed in inference.The proposed model has characteristics that are easy to apply to practical tasks such as inference speed and model management.

• Tuberculosis and Respiratory Diseases
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• v.47 no.3
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• pp.356-364
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• 1999

Backgrounds: Previous reports have revealed a high morbidity and mortality in fatal asthma patients, especially those treated in the medical intensive care unit(MICU). But it has not been well known about the predictable factors for the mortality of fatal asthma(F A) with acute respiratory failure. In order to define the predictable factors for the mortality of FA at the admission to MICU, we analyzed the relationship between the clinical parameters and the prognosis of FA patients. Methods: A retrospective analysis of all medical records of 59 patients who had admitted for FA to MICU at a tertiary care MICU from January 1992 to March 1997 was performed. Results: Over all mortality rate was 32.2% and 43 patients were mechanically ventilated. In uni-variate analysis, the death group had significantly older age ($66.2{\pm}10.5$ vs. $51.0{\pm}18.8$ year), lower FVC($59.2{\pm}21.1$ vs. $77.6{\pm}23.3%$) and lower $FEV_1$($41.4{\pm}18.8$ vs. $61.l{\pm}23.30%$), and longer total ventilation time ($255.0{\pm}236.3$ vs. $98.1{\pm}120.4$ hour) (p<0.05) compared with the survival group (PFT: best value of recent 1 year). At MICU admission, there were no significant differences in vital signs, $PaCO_2$, $PaO_2/FiO_2$, and $AaDO_2$, in both groups. However, on the second day of MICU, the death group had significantly more rapid pulse rate ($121.6{\pm}22.3$ vs. $105.2{\pm}19.4$ rate/min), elevated $PaCO_2$ ($50.1{\pm}16.5$ vs. $41.8{\pm}12.2 mm Hg$), lower $PaO_2/FiO_2$, ($160.8{\pm}59.8$ vs. $256.6{\pm}78.3 mm Hg$), higher $AaDO_2$ ($181.5{\pm}79.7$ vs. $98.6{\pm}47.9 mm Hg$), and higher APACHE III score ($57.6{\pm}21.1$ vs. $20.3{\pm}13.2$) than survival group (p<0.05). The death group had more frequently associated with pneumonia and anoxic brain damage at admission, and had more frequently developed sepsis during disease progression than the survival group (p<0.05). Multi-variate analysis using APACHE III score and $PaO_2/FiO_2$, ratio on first and second day, age, sex, and pneumonia combined at admission revealed that APACHE III score (40) and $PaO_2/FiO_2$ ratio (<200) on second day were regarded as predictive factors for the mortality of fatal asthma (p<0.05). Conclusions: APACHE III score ($\geq$40) and $PaO_2/FiO_2$ ratio (<200) on the second day of MICU, which might reflect the response of treatment, rather than initially presented clinical parameters would be more important predictable factors of mortality in patients with FA.

• Childhood Kidney Diseases
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• v.3 no.2
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• pp.161-169
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• 1999

Purpose : The urinary mass screening program for the detection of proteinuria in school aged population has been performed in Seoul since 1981. Systematic evaluation in corporation with the Seoul School Health Center for students with proteinuria identified in the mass screening has been performed from 1987. The results of urinary mass screening up to 1994 was reported. I report here the results of urinary mass screening from 1995 to 1997 and compare them with previous results and attempt to reveal the significance of urinary mass screening. Objects and Methods : In the 3-year period between 1995 and 1997, annually about 460,000 students comprising 3 different age groups; 5th grade of elementary school, 2nd grade of middle school and 2nd grade of high school were chosen, corresponding to the approximate ages of 11, 14, and 17 years, respectively. These subjects accounted for 26% of total school aged children in Seoul. The screening program was carried out in 3 steps. The 1st test was performed with dipstick at school and the 2nd at the Seoul School Health Center. Those students who showed proteinuria in the 1st and 2nd tests were referred to the hospital. Laboratory examinations including renal biopsies were performed to those students with pathologic proteinuria to clarify the incipient renal diseases. Results : 1) The prevalence of asymptomatic proteinuria was 0.28% in the 1st test. It peaked at the group of 14 years old as 0.34%, compared with 0.26% at the group of 11 years old and 0.24% at the group of 17 years old. It reached to 0.26% in male and 0.30% in female. 2) 25 percent of those having proteinuria at the first test were positive at the second test. 3) The proportion of patients with proteinuria by 3rd test were as follows; 25% of transient proteinuria, 55% of orthostatic proteinuria, 6% of constant proteinuria, 12% of proteinuria with hematuria, and 2% of transient proteinuria with isolated hematuria. Pathologic proteinuria were totaled as 20%. The prevalence of renal diseases among the age group of 7-18 years old was estimated to be 1.4 per 10,000. 4) Renal biopsy performed on 38 children with proteinuria at the third test revealed IgA nephropathy in 17(44%), focal segmental glomerusclerosis in 5(13%), minimal change disease in 4(11%), membranoproliferative glomeronephritis in 3(8%), $Henoch-Sch\"{o}nlein$ purpura nephritis in 3(8%), and others in 6(16%). Therefore, the prevalence of IgA nephropathy among the age group of 7-18 years old was estimated to be 0.64 per 10,000. 5) The prevalence of chronic renal failure was estimated to be 5.7 per 1 million of 7 to 18 years age group. Conclusions : 1) The prevalence of proteinuria in the first screening test was 0.28% and finally only 5% of them showed the pathologic proteinuria at the third test. 2) The prevalence of IgA nephropathy and chronic renal failure were 0.63 per 10,000 and 5.7 per 1 million, respectively among school-aged children in Seoul.

• Radiation Oncology Journal
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• v.14 no.2
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• pp.95-103
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• 1996

Purpose : A retrospective analysis for patients with oropharyngeal carcinoma who were treated with radiation was performed to assess the results of treatment and patterns of failure, and to identify the factors that might influence survival. materials and methods : From March 1985 through June 1993, 53 patients with oropharyngeal carcinoma were treated with either radiation therapy alone or combination of neoadjuvant chemotherapy and radiation therapy at the Department of Radiation Oncology, Kyungpook National University Hospital. Patients' ages ranged from 31 to 73 years with a median age of 54 years. There were 47 men and 6 women, Forty-two Patients ($79.2\%$) had squamous cell carcinoma, 10 patients ($18.9\%$) had undifferentiated carcinoma and 1 patient ($19\%$) had adenoid cystic carcinoma. There were 2 patients with stage I, 12 patients with stage II, 12 Patients with stage III and 27 patients with stage IV. According to the TNM classification, patients were distributed as follows: T1 7, T2 28, T3 10, T4 7, TX 1, and N0 17, Nl 13, N2 21, N3 2. The primary tumor sites were tonsillar region in 36 patients ($67.9\%$), base of the tongue in 12 patients ($22.6\%$), and soft palate in 5 patients ($9.4\%$). Twenty-five patients were treated with radiation therapy alone and twenty-eight Patients were treated with one to three courses of chemotherapy followed by radiation therapy. Chemotherapeutic regimens used were either CF (cisplatin and 5-fluorouracil) or CVB (cisplatin, vincristine and bleomycin). Radiation therapy was delivered 180-200 cGy daily, five times a week using 6 MV X-ray with or without 8-10 MeV electron beams A tumor dose ranged from 4500 cGy to 7740 cGy with a median dose of 7100 cGy. The follow-up time ranged from 4 months to 99 months with a median of 21 months. Results : Thirty-seven patients ($69.8\%$) achieved a CR (complete response) and PR (partial response) in 16 patients ($30.2\%$) after radiation therapy. The overall survival rates were $47\%$ at 2 years and $42\%$ at 3 years, respectively. The median survival time was 23 months. Overall stage (p=0.02) and response to radiation therapy (p=0.004) were significant prognostic factors for overall survival. The 2-year disease-free survival rate was $45.5\%$. T-stage (p=0.03), N-stage (p=0.04) and overall stage (P=0.04) were significant prognostic factors for disease-free survival. Age, sex, histology, primary site of the tumor, radiation dose, combination of chemotherapy were not significantly associated with disease-free survival. Among evaluable 32 Patients with CR to radiation therapy, 12 patients were considered to have failed Among these, 8 patients failed locoregionally and 4 Patients failed distantly. Conclusion : T-stage, N-stage and overall stage were significant prognostic factors for disease-free survival in the treatment of oropharyngeal cancer Since locoregional failure was the predominant pattern of relapse, potential methods to improve locoregional control with radiation therapy should be attempted. More controlled clinical, trials should be completed before acceptance of chemotherapy as a part of treatment of oropharyngeal carcinoma.

• Radiation Oncology Journal
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• v.15 no.2
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• pp.121-128
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• 1997

Purpose : To evaluate the effect of postoperative adjuvant radiation therapy and chemotherapy on the survival, pattern of failure and complication for locally advanced rectal carcinoma Materials and Methods : From October 1992 to September 1995, twenty eight patients with rectal carcinoma were treated by postoperative adjuvant radiation therapy and chemotherapy Radiation therapy was delivered with 6MV and 15MV linear accelerator, 180c0y fractions 5 day per week. Total radiation doses were 5040cGy in $B_{2+3}$ and 5580cGy in $C_{2+3}$. Within 4 weeks after radical surgery. 5-FU$(400mg/m^2/day)\;and\;Leucovorin(20mg/m^2/day)$ were administered by intravenous injection for 4 days during the first and fifth week of radiation therapy. The median follow up was 19 months with a range 2 to 47 months. Results : The 2 year overall survival and disease free survival rates were $78.6\%\;and\;70.8\%$, respectively. The 2 year overall survival was $93.0\%\;in\;B_{2+3}$ and $76.2\%\;in\;C_{2+3}$(p=0.11) The 2 year disease free survival was $79.4\%\;in\;B_{2+3}\;and\;69.2\%\;in\;C_{2+3}(p=0.13)$. The overall failure rate was $21.42\%$(6/28) including $10.72\%$(3/28) locoregional recurrence, $3.62\%$(1/28) distant metastasis and $7.12\%$(2/28) locoregional recurrence with distant metastasis. The overall locoregional recurrence rate was $17.92\%$(5/28). The 2 year locoregional recurrence rates were $13.32\%(2/15)\;and\;23.12\%$(3/13) for respectively for $B_{2+3}\;and\;C_{2+3}$ The difference between the locoregional recurrence of $B_{2+3}\;and\;C_{2+3}$ patients was not significant(p=0.07). Complications developed in 13 patients$(46.42\%)$, including 8 dermatitis, 7 loose stool, 6 leukopenia, 4 tenesmus, 2 diarrhea. In Univariate analysis, there was no statistically significant factor except for tumor grade in locoregional recurrence, disease free survival and overall survival rate(p=0.04, 0.05, 0.04). Conclusion : This study sugges1s that postoperative adjuvant radiation therapy and chemotherapy is effective in patients with locally advanced rectal cancer. Therefore these results need to be confirmed with a long term follow-up and larger number of patients with the further clinical trials including prospective controlled studies.

• Radiation Oncology Journal
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• v.27 no.4
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• pp.181-188
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• 2009

Purpose: The aim of this study was to evaluate the results of postoperative radiotherapy in a case of perihilar cholagiocarcinoma by analyzing overall survival rate, patterns of failure, prognostic factors for overall survival, and toxicity. Materials and Methods: Between January 1998 and March 2008, 38 patients with perihilar cholangiocarcinoma underwent a surgical resection and adjuvant radiotherapy. The median patient age was 59 years (range, 28 to 72 years), which included 23 men and 15 women. The extent of surgery was complete resection in 9 patients, microscopically positive margins in 25 patients, and a subtotal resection in 4 patients. The tumor bed and regional lymphatics initially received 45 Gy or 50 Gy, but was subsequently boosted to a total dose of 59.4 Gy or 60 Gy in incompletely resected patients. The median radiotherapy dose was 59.4 Gy. Concurrent chemotherapy was administered in 30 patients. The median follow-up period was 14 months (range, 6 to 45 months). Results: The 3-year overall survival and 3-year progression free survival rates were 30% and 8%, respectively. The median survival time was 28 months. A multivariate analysis showed that differentiation was the only significant factor for overall survival. The 3-year overall survival was 34% in R0 patients and 20% in R1 patients. No statistically significant differences in survival were found between the 2 groups (p=0.3067). The first site of failure was local in 18 patients (47%). No patient experienced grade 3 or higher acute toxicity and duodenal bleeding developed in 2 patients. Conclusion: Our results suggest that adjuvant RT might be a significant factor in patients with a positive margin following a radical resection. However, there was still a high locoregional recurrence rate following surgery and postoperative radiotherapy. Further study is necessary to enhance the effect of the adjuvant radiotherapy.

• Radiation Oncology Journal
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• v.14 no.3
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• pp.221-228
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• 1996

Purpose : We tried to evaluate the clinical characteristics, the treatment methods, the results of treatments, and the Patterns of failure in ovarian dysgerminoma retrospectively According to the results we would like to suggest the proper management guideline of stage la ovarian dysgerminoma patients who want to maintain fertility. Materials and Methods : Between 1975 and 1990, 34 patients with ovarian dysgerminoma were treated at the Yonsei University Hospital. The case records of these patients have been reviewed for presenting symptoms, treatment methods, local control and survival following treatment. Excluded from analysis were five patients with mixed ovarian germ cell tumors and gonadoblastomas (46,XY) Treatment results of the twenty nine patients were analysed by each treatment modality. Twenty one patients were treated with surgery and postoperative adjuvant radiotherapy (group 2). The other eight patients were treated with operation alone (group 2). The median age of twenty-nine patients was 23 years with a range of 8 to 39 years. Presenting symptoms were abdominal mass (20) pelvic discomfort or pain (5) et al. Radiotherapy was performed by 10MV LINAC or Co-60 teletherapy unit. The total radiation dose of the whole abdomen was 20-25 Gy/3weeks, 1-1.5 Gy/fraction with a boost to the whole pelvis 10-15 Gy/l-2weeks 1.8-2.0 Gy/fraction. Advanced stage disease (stage II or stage III) patients received prophylactic mediastinal and supraclavicular irradiation to a dose of 16-26 Gy. Median duration of follow-up of living patients was 80 months (range 13-201 months). Results : All of the twenty one patients of group 1 were alive without disease ($100\%$). Among the eight patients who were not treated with radiotherapy (group 2), six patients developed local recurrence. Four Patients referred with recurrent disease were treated with salvage radiotherapy. Three of four patients were salvaged and one Patient who had recurrent intra-abdominal disease died of progressed carcinomatosis at 11 months after salvage radiotherapy. The other two patients with recurrence were salvaged with chemotherapy (1 patient) or re-operation (1 Patient). Twenty eight patients remained alive without disease at last follow up, so the 5 year local control rate and 5 year overall survival rate for all groups were $96.6\%$ (28/29), respectively. Among thirteen patients with stage la unilateral tumors seven patients were treated with postoperative radiotherapy and the other six patients were treated with unilateral salpingo-oophorectomy alone. Five patients who did not received radiotherapy developed local failure but all of the recurrent ovarian dysgerminomas were salvaged with radiotherapy, chemotherapy or re-operation. So all the 13 patients with stage la ovarian dysgerminoma were free of disease from 20-201 months (median 80 months). Conclusion : The authors consider external irradiation to be an effective treatment as a complement to surgery in ovarian dysgerminoma. For those patients with disease presenting in stage la tumors who wish to maintain fertility, unilateral salpingo-oophorectomy alone may be curative and spare ovarian function considering excellent salvage rate of recurrent ovarian dysgerminoma in present study.

• Radiation Oncology Journal
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• v.16 no.3
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• pp.311-323
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• 1998

Purpose : Prospective, single arm, Phase I/II clinical trial was performed to assess the efficacy and toxicity of the concurrent chemotherapy and definitive radiotherapy (RT) in patients with previously untreated locally advanced carcinoma of the uterine cervix. Methods and Materials : From Mar 1992 to January 1997, a total of 73 patients with advanced cervical carcinoma were entered on the protocol but 5 patients were excluded in analysis because of patients' refusal of treatment. Their ages ranged from 31 to 77 years, median 58 years. The International Federation of Gynecology and Obstetrics (FIGO) stage distribution was as follows: IIB 46, IIIA 2, IIIB 15 and IVA 5. RT consisted of external beam irradiation to 4,140-5,040 cGy/23-28 fractions plus high dose rate intracavitary treatments to deliver a dose of 30-35 Gy to point A in 6-7 fractions. During the intracavitary treatments parametrial boost was delivered for point B dose of 60 Gy in stage IIB and 65 Gy in stage IIIB. Two cycles of concurrent 5-fluorouracil and cisplatin (FP) chemotherapy (5-fluorouracil 1,000 mg/$m^2$/day continuous infusion for 4 days, day 1-4, 29-32 and cisplatin 20 mg/$m^2$/day intravenous bolus for 3 days day 1-3, 29-31) administered starting on day 1 of RT. Results : The median follow-up was 24 months (range 4-68+). Sixty-four patients were evaluable for survival rate in this protocol: The 5-year actuarial and disease-free survival rate were 52$\%$ and 64$\%$, respectively. The 5-rear actuarial survival for stage IIB and III+IVA patients were 58$\%$ and 36$\%$, respectively The 5-year disease-free survival rate for stage IIB and III+IVA patients were 71$\%$ and 40$\%$, respectively. Of the 68 patients evaluated for patterns of failure, overall recurrence rate was 27.9$\%$ (19/68) : local failure in 5.9$\%$ (4/68), distant metastasis in 10.3$\%$ (7/68) and both in 11.8$\%$ (8/68). Of the 64 patients evaluated for response at one month after the completion of treatment the complete response rate was 78$\%$ (50/64). Concurrent chemoradiation appear to be a well-tolerated regimen but there were two treatment-related deaths. Conclusion : Concurrent chemotherapy of FP with high-dose definitive RT in locally advanced carcinoma of the uterine cervix is feasible and effective with acceptable toxicities. This chemoradiation regimen may offer a modest survival benefit for advanced stage. Further follow-up of these patients will evaluate the impact of this regimen on the long-term local control and their survival.

• Journal of Distribution Science
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• v.10 no.2
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• pp.29-41
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• 2012

This paper undertakes a conceptual review of transaction cost to broaden the understanding of the transaction cost analysis (TCA) approach. More than 40 years have passed since Coase's fundamental insight that transaction, coordination, and contracting costs must be considered explicitly in explaining the extent of vertical integration. Coase (1937) forced economists to identify previously neglected constraints on the trading process to foster efficient intrafirm, rather than interfirm, transactions. The transaction cost approach to economic organization study regards transactions as the basic units of analysis and holds that understanding transaction cost economy is central to organizational study. The approach applies to determining efficient boundaries, as between firms and markets, and to internal transaction organization, including employment relations design. TCA, developed principally by Oliver Williamson (1975,1979,1981a) blends institutional economics, organizational theory, and contract law. Further progress in transaction costs research awaits the identification of critical dimensions in which transaction costs differ and an examination of the economizing properties of alternative institutional modes for organizing transactions. The crucial investment distinction is: To what degree are transaction-specific (non-marketable) expenses incurred? Unspecialized items pose few hazards, since buyers can turn toalternative sources, and suppliers can sell output intended for one order to other buyers. Non-marketability problems arise when specific parties' identities have important cost-bearing consequences. Transactions of this kind are labeled idiosyncratic. The summarized results of the review are as follows. First, firms' distribution decisions often prompt examination of the make-or-buy question: Should a marketing activity be performed within the organization by company employees or contracted to an external agent? Second, manufacturers introducing an industrial product to a foreign market face a difficult decision. Should the product be marketed primarily by captive agents (the company sales force and distribution division) or independent intermediaries (outside sales agents and distribution)? Third, the authors develop a theoretical extension to the basic transaction cost model by combining insights from various theories with the TCA approach. Fourth, other such extensions are likely required for the general model to be applied to different channel situations. It is naive to assume the basic model appliesacross markedly different channel contexts without modifications and extensions. Although this study contributes to scholastic research, it is limited by several factors. First, the theoretical perspective of TCA has attracted considerable recent interest in the area of marketing channels. The analysis aims to match the properties of efficient governance structures with the attributes of the transaction. Second, empirical evidence about TCA's basic propositions is sketchy. Apart from Anderson's (1985) study of the vertical integration of the selling function and John's (1984) study of opportunism by franchised dealers, virtually no marketing studies involving the constructs implicated in the analysis have been reported. We hope, therefore, that further research will clarify distinctions between the different aspects of specific assets. Another important line of future research is the integration of efficiency-oriented TCA with organizational approaches that emphasize specific assets' conceptual definition and industry structure. Finally, research of transaction costs, uncertainty, opportunism, and switching costs is critical to future study.