• Title/Summary/Keyword: Difference-in-Differences Method

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Technical Inefficiency in Korea's Manufacturing Industries (한국(韓國) 제조업(製造業)의 기술적(技術的) 효율성(效率性) : 산업별(産業別) 기술적(技術的) 효율성(效率性)의 추정(推定))

  • Yoo, Seong-min;Lee, In-chan
    • KDI Journal of Economic Policy
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    • v.12 no.2
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    • pp.51-79
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    • 1990
  • Research on technical efficiency, an important dimension of market performance, had received little attention until recently by most industrial organization empiricists, the reason being that traditional microeconomic theory simply assumed away any form of inefficiency in production. Recently, however, an increasing number of research efforts have been conducted to answer questions such as: To what extent do technical ineffciencies exist in the production activities of firms and plants? What are the factors accounting for the level of inefficiency found and those explaining the interindustry difference in technical inefficiency? Are there any significant international differences in the levels of technical efficiency and, if so, how can we reconcile these results with the observed pattern of international trade, etc? As the first in a series of studies on the technical efficiency of Korea's manufacturing industries, this paper attempts to answer some of these questions. Since the estimation of technical efficiency requires the use of plant-level data for each of the five-digit KSIC industries available from the Census of Manufactures, one may consture the findings of this paper as empirical evidence of technical efficiency in Korea's manufacturing industries at the most disaggregated level. We start by clarifying the relationship among the various concepts of efficiency-allocative effciency, factor-price efficiency, technical efficiency, Leibenstein's X-efficiency, and scale efficiency. It then becomes clear that unless certain ceteris paribus assumptions are satisfied, our estimates of technical inefficiency are in fact related to factor price inefficiency as well. The empirical model employed is, what is called, a stochastic frontier production function which divides the stochastic term into two different components-one with a symmetric distribution for pure white noise and the other for technical inefficiency with an asymmetric distribution. A translog production function is assumed for the functional relationship between inputs and output, and was estimated by the corrected ordinary least squares method. The second and third sample moments of the regression residuals are then used to yield estimates of four different types of measures for technical (in) efficiency. The entire range of manufacturing industries can be divided into two groups, depending on whether or not the distribution of estimated regression residuals allows a successful estimation of technical efficiency. The regression equation employing value added as the dependent variable gives a greater number of "successful" industries than the one using gross output. The correlation among estimates of the different measures of efficiency appears to be high, while the estimates of efficiency based on different regression equations seem almost uncorrelated. Thus, in the subsequent analysis of the determinants of interindustry variations in technical efficiency, the choice of the regression equation in the previous stage will affect the outcome significantly.

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The Clinical Effects of Leukocyte-Depleting Filter on Cardiopulmonary Bypass (체외순환 시 백혈구 제거필터 사용의 임상효과)

  • 박경택;최석철;최국렬;정석목;최강주
    • Journal of Chest Surgery
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    • v.34 no.6
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    • pp.454-464
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    • 2001
  • Background: It has been recognized that systemic inflammatory reaction and oxygen free radical formed by activated leukocyte in the procedure of cardiopulmonary bypass(CPB) frequently produce postoperative cardiac and pulmonary dysfunction. The purpose of this study was to evaluate the efficacy of leukocyte-depleting filters in the cardiopulmonary bypass circuit for patients undergoing open heart surgery(OHS). Material and method: The study involved 15 patients who underwent OHS with a Leukoguard-6 leukocyte filter placed in the arterial limbs of the bypass circuit(filter group, n=15) and 15 patients who did not have the filter(control group, n=15). We analyzed the differences between the groups in intraoperative changes of peripheral blood leukocyte and platelet counts, pre- and postbypass changes of malondialdehyde(MDA), troponin-T(TnT), 5'-nucleotidase(5'-NT) in coronary sinus blood, spontaneous recovery rate of heart beat after CPB, pre-and postoperative cardiac index(Cl) and pulmonary vascular resistance(PVR), and the amounts of postoperative bleeding and sternal wound complication. Result: During CPB, total leukocyte count of the filter group(9,567$\pm$ 842/㎣) was significantly less than that of the control group(13,573+1,167/㎣) (p<0.01), but there was no significant difference in platelet count between the groups. Postoperative levels of MDA(3.78+0.32 $\mu$mol/L vs 5.86+0.65 $\mu$mo1/L, p<0.01), TnT(0.40$\pm$0.04 ng/mL vs 0.59$\pm$0.08 ng/mL, p<0.05) and 5'-NT(3.88$\pm$0.61 U/L vs 5.80$\pm$0.90 U/L, p<0.05) were all significantly lower in the filter group than the control group. Postoperative Cl was higher in the filter group than the control group(3.26$\pm$0.18 L/$m^2$min vs 2.75$\pm$0.17 L/$m^2$/min, p=0.05). PVR of the filter group was lower than that of the control group(65.87$\pm$7.59 dyne/sec/cm$^{5}$ vs 110.80+12.22 dyne/sec/cm$^{5}$ , p<0.01). Spontaneous recovery rate of heart beat in the filter group was higher than that in the control group(12 patients vs 8 patients, p<0.05). Postoperative wound infection occurred in one case in the filter group and 4 case in the control group(p<0.05). Postoperative 24 hour blood loss of the filter group was more than that of the control group (614$\pm$107 mL vs 380+71 mL, p=0.05).

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The Effect of Spiritual Nursing Intervention on Anxiety of the Hospice Patients (영적 간호중재가 호스피스 환자의 불안에 미치는 효과)

  • Yoon, Mae-Ok
    • Journal of Hospice and Palliative Care
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    • v.4 no.1
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    • pp.47-56
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    • 2001
  • Purpose : Surveying the effects on drop the anxiety of the hospice patients in spiritual nursing intervention with a quasi-experimental design using non-equivalent contrast group non-synchronized design to try in order to give the support which provide a holistic and individualizational nursing to comfort of hospice patients. Method : The results of survey were collected from 67 patients(67 subjects comprised 37 hospice patients of the experimental group and 30s of contrast) who were given hospice care from July to September of 2000 at the General Hospital in Cheon Ju city. The tool was used Spielberger's State Anxiety Scale, and the difference in the level of dropping anxiety among patient groups was analyzed with the mean, standard deviation, $x^2-test$. t-test and paired t-test. The spiritual nursing intervention was carried out through Hymn, Scripture, prayer, the therapeutic use of self over a period of three weeks. Results : 1) In general characters, men were a many more of the objects and the average age of the experimental and contrast group was 59.6, 55.9 respectively. The family of living together was $2{\sim}3$ members of most part. 2) There were not significant differences in the general, disease and therapeutic, religional characters between the experimental and contrast group. 3) The majority of the objects were cancer patients in disease and therapeutic characters(Experimental : 92%, Contrast : 95%). 4) After the spiritual nursing intervention state anxiety of the experimental group were remarkably lower than those of the contrast (t=-5.987, P=0.000). 5) Decreasing rate in the anxiety scores of before and post facto of the experimental group were remarkably lower than those of the contrast (t=6.237, P=0.000). Conclusion : The hospice patients who were offered spiritual nursing intervention became much lower than those who were not offered it in anxiety. Spiritual nursing intervention can be suited to field with one program of an effective that that relieved their anxieties. It is not only a very short time but has quite a little findings in part of spiritual nursing intervention. Therefore, further study in this field is necessary to concrete and substantial investigate in order to more and more increasing hospice patients in 21st century.

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The effect of dental hygiene students' knowledge and attitude toward the elderly on the discrimination of the elderly (치위생학과 학생들의 노인에 대한 지식 및 태도가 노인차별주의에 미치는 영향)

  • Young-Sun Kim;Jung-Hwa Lee
    • Journal of Korean Dental Hygiene Science
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    • v.6 no.2
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    • pp.129-139
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    • 2023
  • Background: The elderly population aged 65 or older in Korea is expected to continue to increase to 18.4% in 2023, and to enter a super-aged society at 20.6% in 2025. In clinical practice, the elderly discrimination of dental hygienists may experience difficulties during dental hygiene treatment due to an increase in the number of elderly patients due to aging, which can lead to maladjustment to work and turnover, so education on the understanding of the elderly is essential for students in the Department of Dentistry, who are prospective dental hygienists. Accordingly, a study was conducted to prepare for a super-aged society by studying the relationship between elderly discrimination and the knowledge and attitudes of the elderly, and to change the curriculum of universities and develop programs related to the elderly. Method: 204 students enrolled in the Department of Dentistry in D area were analyzed using the SPSS/WIN 25.0 program. The subject's geriatric discrimination, knowledge about the elderly, and attitude toward the elderly were calculated as the mean and standard deviation. T-test and one-way ANOVA were performed to verify the difference in geriatric discrimination according to the general characteristics of the subject, with a Scheffe' test applied for post-hoc analysis. Correlation analysis was conducted on the subject's geriatric discrimination, knowledge about the elderly, and attitudes toward the elderly. Results: Geriatrics scored 2.03±0.36 out of 4. Knowledge about the elderly was categorized as follows: physical domain 0.57±0.15; social domain 0.36±0.17; and psychological domain 0.35±0.20. The attitude toward the elderly was 3.86±0.27. Knowledge of the elderly averaged 11.27±3.30 points out of 25. The question with the highest percentage of correct answers to knowledge about the elderly was 'physical strength tends to decrease with age', which was 93.1%. The attitude toward the elderly according to the general characteristics of the study subjects showed significant differences in gender (p=0.040), age (p=0.026), and life experience with grandparents (p=0.001). The elderly discrimination of the study subjects showed a negative correlation in both attitude and knowledge toward the elderly, and among the elderly discrimination, there was a high positive correlation with regard to emotional avoidance (r=.892, p<0.001). Conclusion: College students are the leading players in caring for the elderly and are directly affected by aging social problems. Therefore, it is considered necessary to apply various programs in the state, society, and educational institutions to avoid negative prejudices that lead to positive thinking and discrimination against the elderly.

The Relation Between Bronchodilator Response, Airway Hyperresponsiveness and Serum Eosinophil Cationic Protein (ECP) Level in Moderate to Severe Asthmatics (중증 및 중등증 기관지천식 환자에서 기도과민성과 기관지확장제 반응성 및 혈청 Eosinophil Cationic Protein(ECP)와의 관계)

  • Park, Sung-Jin;Kang, Soon-Bock;Kwon, Jung-Hye;Lee, Sang-Hoon;Jung, Do-Youg;Yoo, Ji-Hoon;Kim, Sang-Hoon;Kim, Jae-Yeol;Park, In-Won;Choi, Byoung-Whui
    • Tuberculosis and Respiratory Diseases
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    • v.50 no.2
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    • pp.196-204
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    • 2001
  • Background : Bronchial asthma is characterized by a reversible airway obstruction, airway hyperresponsiveness, and eosinophilic airway inflammation. The bronchodilator response(BDR) after short acting beta agonist inhalation and PC20 with methacholine inhalation are frequently used for diagnosing bronchial asthma. However, the relationship between the presence of a bronchodilator response and the degree of airway hyperresponsiveness is uncertain. Therefore, the availability of a eosinophil cationic protein (ECP) and a correlation ECP with a bronchodilator response and airway hyperresponsiveness was investigated. Method : A total 71 patients with a moderate to severe degree of bronchial asthma were enrolled and divided into two groups. 31 patients with a positive bronchodilator response and 38 patients with a negative bronchodilator response were evaluated. In both groups, the serum ECP, peripheral blood eosinophil counts, and total IgE level were measured and the methacholine bronchial provocation test was examined. Results : There were no differences observed in age, sex, atopy, and baseline spirometry in both groups. The peripheral eosinophil counts showed no difference in both groups, but the ECP level in group 1 (bronchodilator responder group) was higher than in group 2(non-bronchodilator responder group) ($22.4{\pm}20.7$ vs $14.2{\pm}10.4$, mean$\pm$SD). The PC20 in group 1 was significantly lower than in group 2 ($1.14{\pm}1.68$ vs $66{\pm}2.98$). There was a significant positive correlation between the BDR and ECP, and a negative correlation between the bronchial hyperresponsiveness and ECP. Conclusion : The bronchodilator response significantly correlated with the bronchial hyperresponsiveness and serum ECP in the moderate to severe asthma patients. Hence, the positive bronchodilator response is probably related with active bronchial inflammation and may be used as a valuable index in treatment, course and prognosis of bronchial asthma.

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Clinical Evaluation on Transbronchial Needle Aspiration (TBNA) of Subcarinal Lymph Node in Lung Cancer (폐암에서 기관 분기부하 림프절의 경기관지 침흡인 세포검사에 관한 연구)

  • Kang, Yu-Ho;Choi, In-Seon;Jung, Ik-Ju;Park, Jai-Hee;Lee, Shin-Seok;Lee, Min-Su;Kim, Young-Cheol;Park, Kyung-Ok;Jung, Sang-Woo
    • Tuberculosis and Respiratory Diseases
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    • v.40 no.2
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    • pp.177-184
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    • 1993
  • Background: Accurate staging of bronchogenic carcinoma is important in determining resectability and metastasis of tumor to the subcarinal nodes is generally believed to indicate poor prognosis. The technique of Transbronchial needle aspiration (TBNA) has offered a safe & effective way to asscess mediastinal lymph node involvement in the staging of lung cancer. We performed TBNA in patients who were suspected lung cancer to evaluate the clinical usefulness of the TBNA. Method: TBNA of the subcarinal lymph node was performed at the time of initial diagnostic bronchoscopy in 60 patients with suspected lung cancer, and 42 cases of histologically proved bronchogenic cancer were analized. Results: The frequency of adequate samples by transbronchial needle aspiration (TBNA) was 81% and the positive rate of malignant cells by TBNA was 14.7%. There were no differences in positive rates by tumor cell types. In patients with thickened carina on bronchoscopy, the TBNA was positive in 33.3% as compared to 5.3% of normal carina on bronchoscopy, and the difference was statistically significant (p<0.05). In patients with enlarged subcarinal lymph node on chest CT, the positive rate of malignant cells (50.0%) was higher than that of normal sized subcarinal lymph node on chest CT (4.8%) (p<0.01). There were no specific complications in the TBNA procedure. Conclusion: TBNA is a relatively safe procedure and it offers the possibility of avoiding the cost and morbidity of surgical staging in patients especially whose carina is thickened on bronchoscopy and whose subcarinal LN was enlarged on chest CT.

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Psychological benefits of bench-step aerobics program in overweight or obese adult women: its effects on anger, exercise self-efficacy, exercise-related affect, and body image (과체중 및 비만 성인 여성 대상 스텝운동 프로그램의 심리적 효과: 분노, 운동관련 자기 효능감, 운동관련 정서 및 신체상에 미치는 효과)

  • Lee, Mi-Ra;Kim, Wan-Soo
    • Korean Journal of Health Education and Promotion
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    • v.24 no.5
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    • pp.119-135
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    • 2007
  • Objectives: The efficacy, feasibility, and safety of bench-step aerobics (BSA) program in overweight or obese Korean adult women have been implied. However, there has been almost no evidence for its psychological benefits. As such, the purpose of this study was to investigate the psychological benefits of BSA program in overweight or obese (body mass index ${\geq}\;23\;kg/m^2$) Korean adult women. Method: Anger, exercise self-efficacy, exercise-related affect, and body image of overweight or obese women who participated in a 12-week BSA program (n=15) were compared with those of their counterparts in the control group (n=13). Subjects were selected among public health center visitors and those recruited by putting an advertisement in local newspapers and the public health center homepage. Data from the exercise and control groups were collected before and after the 12-week BSA program (from August to November in 2006) at the public health centers. The exercise program consisted of 45 to 60 min moderate-intensity (40/50 to 50/60% of their hear rate reserve) BSA performed for 3 days a week. Results: After the BSA program, body image of the subjects in the exercise group was significantly improved and there was a significant difference between the exercise and control groups. Anger, exercise self-efficacy, and exercise-related affect were improved after the BSA program but the changes did not reach the level of statistical significance and there were no significant differences between the exercise and control groups. Conclusions: In conclusion, BSA appears to significantly enhance body image in overweight or obese Korean adult women but its effects on anger, exercise self-efficacy, and exercise-related affect do not appear to be statistically significant. Further studies involving different subjects, particularly whose levels of anger are high or whose levels of exercise-related affect are low to exclude the influence of the ceiling or floor effect, are warranted in a randomized controlled design.

Study on Measurements of the Mandible BMD According to the ROI Variation (관심영역 변화에 따른 하악골 골밀도 측정에 대한 연구)

  • Tak, Jeong-Nam
    • Journal of radiological science and technology
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    • v.32 no.3
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    • pp.271-276
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    • 2009
  • The aim of this study was to evaluate the effect of Bone Mineral Density(BMD) at mandible. So, we studied how to measure the BMD at mandible using DEXA(Dual energy X-ray absorptiometry, DEXA) by Horner er al (1996) and knew reproducibility of the measurements. Thirty-five patients (13 men, 22 women, mean age : 25.4 years) were examined using the GE Lunar Prodigy Advance(LUNAR Corporation, madison, USA). They were examined in Semiprone position of their body and true lateral position of their mandible selected the Lumbar lateral mode. We used the custom mode in analysis when ROI (area $30{\times}2.5\;mm^2$). Three ROIs ($30{\times}2.5\;mm^2$, $50{\times}2.5\;mm^2$, $20{\times}2.5\;mm^2$) were located each at the two different sites of the mandible (angle of mandible and mental symphysis) and BMD was measured. Differences in BMD measurement was statistically compared according to the size and location of ROI. BMD was $1.320{\pm}0.358g/cm^3$ in men and was $1.152{\pm}0.340g/cm^3$ in women. BMD at the angle of mandible was $1.201{\pm}0.361g/cm^3$ in men and was $1.025{\pm}0.377g/cm^3$ in women. BMD of men at the mental symphysis was $1.434{\pm}0.341g/cm^3$ and that of women was $1.19{\pm}0.358g/cm^3$. With the ROI of $20{\times}2.5\;mm^2$, BMD was $1.262{\pm}0.384g/cm^3$ in men and was $1.113{\pm}0.357g/cm^3$ in women. With the ROI of $50{\times}2.5\;mm^2$, BMD of men was $1.320{\pm}0.358g/cm^3$ and that of women was $1.129{\pm}0.340g/cm^3$. There was a statistically significant difference of BMD according to the size and location of ROI. When measuring mandible BMD, there are good for increasing ROI and locate between ramus and mental symphysis. Especially following exam, refer to same size and location with fore exam. According to study which measure mandible BMD, It's correct to measure better a portion of mandible then whole of BMD. Using DEXA protocol is studied good for the additional study to compare the BMD at mandible. Later date, It will be good for measurement value in implant and bone graft quantitatively. Using DEXA method gain BMD threshold value in korean.

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Effect of Fabric Sensor Type and Measurement Location on Respiratory Detection Performance (직물센서의 종류와 측정 위치가 호흡 신호 검출 성능에 미치는 효과)

  • Cho, Hyun-Seung;Yang, Jin-Hee;Lee, Kang-Hwi;Kim, Sang-Min;Lee, Hyeok-Jae;Lee, Jeong-Hwan;Kwak, Hwi-Kuen;Ko, Yun-Su;Chae, Je-Wook;Oh, Su-Hyeon;Lee, Joo-Hyeon
    • Science of Emotion and Sensibility
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    • v.22 no.4
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    • pp.97-106
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    • 2019
  • The purpose of this study was to investigate the effect of the type and measurement location of a fabric strain gauge sensor on the detection performance for respiratory signals. We implemented two types of sensors to measure the respiratory signal and attached them to a band to detect the respiratory signal. Eight healthy males in their 20s were the subject of this study. They were asked to wear two respiratory bands in turns. While the subjects were measured for 30 seconds standing comfortably, the respiratory was given at 15 breaths per minute were synchronized, and then a 10-second break; subsequently, the entire measurement was repeated. Measurement locations were at the chest and abdomen. In addition, to verify the performance of respiratory measurement in the movement state, the subjects were asked to walk in place at a speed of 80 strides per minute(SPM), and the respiratory was measured using the same method mentioned earlier. Meanwhile, to acquire a reference signal, the SS5LB of BIOPAC Systems, Inc., was worn by the subjects simultaneously with the experimental sensor. The Kruskal-Wallis test and Bonferroni post hoc tests were performed using SPSS 24.0 to verify the difference in measurement performances among the group of eight combinations of sensor types, measurement locations, and movement states. In addition, the Wilcoxon test was conducted to examine whether there are differences according to sensor type, measurement location, and movement state. The results showed that the respiratory signal detection performance was the best when the respiratory was measured in the chest using the CNT-coated fabric sensor regardless of the movement state. Based on the results of this study, we will develop a chest belt-type wearable platform that can monitor the various vital signal in real time without disturbing the movements in an outdoor environment or in daily activities.

Influences of Rate of Artificial Insemination Following Estrus Induction in Dog (개에서 발정유도가 인공수정효율에 미치는 영향)

  • 이영락;강태영;최상용
    • Journal of Embryo Transfer
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    • v.18 no.1
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    • pp.61-68
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    • 2003
  • Considerable attention has been focused on the cryopreservation of semen and estrus induction in dog, as consequence of poor productivity caused by long anestrus period, in order to enhance the productivity of youngs and to preserve the breeds. The objectives of this study were to improve reproductive efficiency of artificial insemination with fresh- and frozen-semen following estrus induction in dog. Fifty infertilie dogs (age 2~3 years) were selected fur the study and divided into three different estrus induction treatment groups. Group 1 : dogs (n=15) were given clomifene (0.1 mg/kg) orally f3r five days at 12 hr intervals. Croup 2: dogs (n=15) were given bromocriptine (50 $\mu$g/kg) orally for five days at 12 hr intervals, followed by single injection intravenously of 500 IU GnRH (Croup 3, n=20) when pro-estrus occurred. After being treated, the dogs were evaluated fur the rates of estrus induction and time interval lapses from treatment to beginning of the pro-estrus. The rates of pregnancy in estrus inducted dogs mated naturally compared to those inseminated artificially with ejaculated fresh semen and frozen-thawed semen. Estrus detection was performed using the method of vaginal smear and confirmed by the plasma progesterone assay. Pregnancy was confirmed by ultrasonograpy on day 25, 35 and 55 post insemination. The ejaculated semen was exposed to a mixture of Tris extender with cryoprotectant (Trisma, 81 mM; TES, 209 mM; citric acid, 6 mM; glucose, 5 mM; glycerol, 8%) and cryopreserved gradually by slow-cooling at 17 co above the surface of liquid nitrogen (L$N_2$) for 23 min. The use of fresh semen, the pregnancy rates were observed 66.6, 66.6, 75.0 and 83.3% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. The use of frozen-thawed semen, the pregnancy rates were observed 66.6, 33.3, 50.0 and 60.0% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. No difference was observed in the number of offspring produced among natural estrus and treated groups inseminated with fresh or frozen-thawed semen. In conclusion, there was no significant differences in the pregnancy rate of dogs between group treated with a combination of GnRH and bromocriptine and group treated clomifene or bromocriptine only. However, frozen-thawed semen can be used successfully fur artificial insemination in dog.