• Title/Summary/Keyword: Statistical Change-Point Analysis

Search Result 115, Processing Time 0.026 seconds

The Study on the Economic Appraisal of Fishing Port Investments (어항투자사업의 경제성 평가에 관한 연구)

  • 정형찬
    • The Journal of Fisheries Business Administration
    • /
    • v.14 no.2
    • /
    • pp.15-68
    • /
    • 1983
  • From the economic point of view the fishing port is the complex of installations on land, organized to serve the fishing fleet and its cargo, and is the main link in the production chain of all components of the fishing industry, with the aim of achieving the planned targets with the minimum cost. Fishing port investment decisions have had significant impact on the development aims of Korean fisheries. Fishing port investments in Korea are made mostly by public or semipublic port authorities. Such investments should be judged not purely on the basis of financial profitability but rather on the extent to which they serve the development aims of the fishing industry. This makes the economic appraisal process more complex and presents certain problems in correctly quantifying the economic costs and benefits of the fishing port projects. This study concentrates more on the theoretical economic appraisal models than on the purely financial aspects of fishing port investments and points out the difference between the two approaches. In the result, there is clearly an element of judgment as to whether or not a shadow price needs to be used in estimating economic benefits and costs. From this viewpoint, some attempts are made to provide definitions of the possible economic benefits and costs, and methods for estimating and evaluating them in Part III and IV. Especially queueing theory is applied in the calculation of economic benefits. When a project is contemplated and analysis shows it to Lave a positive NPV, one question that arises is whether it should be implemented now or delayed. In this paper, the first year rate of return method is regarded as a more concise way of solving the timing of investment, At the end of Part IV, risk analysis of fishing port investments is considered. It can be handled in a number of ways, ranging from informal judgment to complex statistical analyses involving large-scale computer models, This paper recommends that evaluators of fishing port investments use the sensitivity analysis indicating exactly how much NPV will change in response to a given change in an input variable, other things held constant. Decisions regarding the amount of capacity to provide must be made in fishing port investments. Providing too much service would involve excessive capital costs. On the other hand, not providing enough service capacity would cause the waiting line of fishing vessels to become excessively long at times. Therefore, in Part V, the optimal number of berths and berth productivity in fishing port are defined as follows: Minimize E(TC) = E(WC)+E(SC) The minimum of this function is the solution and that is the optimal number of berth and berth productivity in fishing port.

  • PDF

The Evaluation of Soft and Hard Tissue Change for Retraction of Lower Anterior Tooth in Bimaxillary Protrusion Patients according to Two Different Therapeutic Methods: Mandibular Anterior Segmental Osteotomy and Orthodontic Treatment with Teeth Extraction (양악전돌증 환자에서 하악 6전치 후방 이동 시 치료 방법에 따른 하악 경조직과 연조직의 변화: 하악 전방분절골절단술과 발치 교정 치료)

  • Kim, Young-Joo;Kim, Kyung-A;Yu, Yong-Jae;Ryu, Kyung-Sun;Ryu, Jeong-Min;Ohe, Joo-Young;Kim, Su-Jung;Kim, Seoung-Hun;Lee, Baek-Soo
    • Maxillofacial Plastic and Reconstructive Surgery
    • /
    • v.34 no.4
    • /
    • pp.246-251
    • /
    • 2012
  • Purpose: The purpose of the study is to evaluate the effectiveness of anterior segmental osteotomy (ASO) in bimaxillary protrusion (BP) patients by comparison between the mandibular soft and hard tissue changes from orthodontic treatment and ASO. Methods: All 44 patients were diagnosed with BP in Kyung-Hee Medical Center. Orthodontic treatment with teeth extractions were underwent by 23 patients (Group A) and 21 patients underwent ASO (Group B). Mandibular soft and hard tissue changes were measured and evaluated, which were based on the vertical and horizontal reference line in lateral cephalometric radiographs. Statistical significance between the changes and correlation between each measurement were analyzed. Results: The amount of B point movement was lesser than that of the lower incisal tip (LIT) retraction, and LIT was tilted lingually in group A. The posterior movement discrepancy between LIT and B point was insignificant, and the inclination of lower incisor was not changed in group B. The soft tissues, including the lower lip, showed a posterior movement and reduction in the depth of mento-labial groove. According to the correlation analysis, the movement of the lower incisor was significantly related to the movement of the lower lip in group A, and the movement of the lower incisor was significantly related to that of the movement of lower lip, B point and Pog in group B. Conclusion: The orthodontic treatment in BP patients results in posterior tilting movement of the lower incisor, but ASO results in the bodily movement of the lower incisor. Consequently, ASO is more effective in BP cases because it ensures the controlled movement of the lower incisors.

Accuracy of artificial intelligence-assisted landmark identification in serial lateral cephalograms of Class III patients who underwent orthodontic treatment and two-jaw orthognathic surgery

  • Hong, Mihee;Kim, Inhwan;Cho, Jin-Hyoung;Kang, Kyung-Hwa;Kim, Minji;Kim, Su-Jung;Kim, Yoon-Ji;Sung, Sang-Jin;Kim, Young Ho;Lim, Sung-Hoon;Kim, Namkug;Baek, Seung-Hak
    • The korean journal of orthodontics
    • /
    • v.52 no.4
    • /
    • pp.287-297
    • /
    • 2022
  • Objective: To investigate the pattern of accuracy change in artificial intelligence-assisted landmark identification (LI) using a convolutional neural network (CNN) algorithm in serial lateral cephalograms (Lat-cephs) of Class III (C-III) patients who underwent two-jaw orthognathic surgery. Methods: A total of 3,188 Lat-cephs of C-III patients were allocated into the training and validation sets (3,004 Lat-cephs of 751 patients) and test set (184 Lat-cephs of 46 patients; subdivided into the genioplasty and non-genioplasty groups, n = 23 per group) for LI. Each C-III patient in the test set had four Lat-cephs: initial (T0), pre-surgery (T1, presence of orthodontic brackets [OBs]), post-surgery (T2, presence of OBs and surgical plates and screws [S-PS]), and debonding (T3, presence of S-PS and fixed retainers [FR]). After mean errors of 20 landmarks between human gold standard and the CNN model were calculated, statistical analysis was performed. Results: The total mean error was 1.17 mm without significant difference among the four time-points (T0, 1.20 mm; T1, 1.14 mm; T2, 1.18 mm; T3, 1.15 mm). In comparison of two time-points ([T0, T1] vs. [T2, T3]), ANS, A point, and B point showed an increase in error (p < 0.01, 0.05, 0.01, respectively), while Mx6D and Md6D showeda decrease in error (all p < 0.01). No difference in errors existed at B point, Pogonion, Menton, Md1C, and Md1R between the genioplasty and non-genioplasty groups. Conclusions: The CNN model can be used for LI in serial Lat-cephs despite the presence of OB, S-PS, FR, genioplasty, and bone remodeling.

The practical study of contralateral therapeutic theory in acupuncture approach -about the change in the blind spot mapping pre and post acupuncture- (針의 巨刺法에 對한 實證的 硏究 -眼球의 Blind spot 變化에 對하여-)

  • Woo, Young-Min;Nam, Young
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
    • /
    • v.13 no.2
    • /
    • pp.200-210
    • /
    • 2000
  • objective to ascertain whether the concept of the therapeutic side is associated with changes in the blind sport mapping that represents the brain function. design Physiological blind spot maps were used as an integer of brain activity before and after acupuncture needling on the meridian point Hapkok(合谷) and Techung(太衝) in the unilateral side decided by double-blind controlled study(20 subjects). setting outpatient clinic participants: adult volunteers intervention twenty subjects were divided into two comparative groups and underwent specific acupuncture therapy on the unilateral side. Blinded examiners obtained reproducible pre and post-acupuncture cortical maps, which were subjected to statistical analysis. main outcome measures Brain activity was demonstrated by reproducible circumferential measurements of cortical hemispheric blind spot maps before and after acupuncture on the unilateral side. in case of acupuncture needling on the ipsilateral side of an enlarged side of bilnd spot, there were reduction of blind spot in 7 cases of 10 subjects, and enlargement in 3 cases. in case of acupuncture needling on the contralateral side of the enlarged side of blind spot, there were enlargement of blind spot in 6 cases of 10 subjects, and reduction in 4 cases. results the significant changes in the blind spots before and after acupuncture were observed Acupuncture needlings on the ipsilateral or contralateral side of an enlarged cortical map were associated with the concept of the therapeutic side traditionally accepted in the oriental medical society. Acupuncture needling on the ipsilateral side of an enlarged blind spot map is associated with the reduction of map, and increaed contralateral cortical activity. Acupuncture needling on the side opposite an enlarged blind spot map is associated with the enlargement of map, and decreased cortical activity. conclusion Reproducible maps of cortical responses can be used to measure the neurological consequences of acupuncture needling. Acupuncture can affect the somatic sensory informations that reach to the contralateral thalamus, and so affect thalamic integration. we found that acupuncture therapy may be associated with an increase or a decrease in brain function depending on the side of acupuncture needling. thus, the traditional concept of the contralateral therapeutic theory in acupuncture approach has the clinical significance in the view of brain function.

  • PDF

The Measurement and Analysis by Free Space Scatter Dose Distribution of Diagnostic Radiology Mobile Examination Area (영상의학과 이동검사 영역의 공간선량 분포에 대한 측정 및 분석)

  • Kim, Sung-Kyu;Son, Sang-Hyuk
    • Korean Journal of Digital Imaging in Medicine
    • /
    • v.11 no.1
    • /
    • pp.5-13
    • /
    • 2009
  • There are several reasons to take X-ray in case of inpatients. Some of them who cannot ambulate or have any risk if move are taken portable X-ray at their wards. Usually, in this case, many other people-patients unneeded X-ray test, family, hospital workers etc-are indirectly exposed to X-ray by scatter ray. For that reason I try to be aware of free space scatter dose accurately and make the point at issue of portable X-ray better in this study. kVp dose meter is used for efficiency management of portable X-ray equipment. Mobile X-ray equipment, ionization chamber, electrometer, solid water phantom are used for measuring of free space scatter dose. First of all the same surroundings condition is made as taken real portable X-ray, inquired amount of X-ray both chest AP and abdomen AP most frequently examined and measured scatter ray distribution of two tests individually changing distance. In the result of measuring horizontal distribution with condition of chest AP it is found that the mAs is decreased as law of distance reverse square but no showed mAs change according to direction. Vertical distribution showed the mAs slightly higher than horizontal distribution but it isnt found out statistical characteristic. In abdomen AP, compare with chest AP, free space scatter dose is as higher as five-hundred times and horizontal, vertical distribution are quite similar to chest AP in result. In portable X-ray test, in order to reduce the secondary exposure by free space scatter dose first, cut down unnecessary portable order the second, set up the specific area at individual ward for the test the third, when moving to a ward for the X-ray test prepare a portable shielding screen. The last, expose about 2m apart from patients if unable to do above three ways.

  • PDF

An Analysis of the Relationship between Domestic and Overseas Investment Using a Regression Tree (회귀나무를 이용한 국내외 투자간 관계 분석)

  • Chang, Young-Jae
    • The Korean Journal of Applied Statistics
    • /
    • v.24 no.3
    • /
    • pp.455-464
    • /
    • 2011
  • Overseas direct investment is constantly on the rise, while domestic investment has been slowing and has led to concerns that the expansion of overseas investment may be weakening domestic investment. Considering the change of environment as economic growth, this paper analyzes the relationship between domestic and overseas investment using a regression tree. The result shows that overseas investment substituted domestic investment in the past (before 1985); however, they compensated for each other during the rapid growth period based on exports (1986-1997). The relationship turns out to be insignificant after the Asian currency crisis(after 1998). In addition, this paper also examines the factors determining domestic facilities investment and overseas direct investment at each stage of the changes in their influence due to globalization. Taking into account the results, we need to re-evaluate the current pattern of corporate investment apart from the past restricted point of view to help domestic enterprises efficiently utilize the international production network and resources.

Evaluation of proximal contact strength by postural changes

  • Kim, Hee-Sun;Na, Hyun-Joon;Kim, Hee-Jung;Kang, Dong-Wan;Oh, Sang-Ho
    • The Journal of Advanced Prosthodontics
    • /
    • v.1 no.3
    • /
    • pp.118-123
    • /
    • 2009
  • STATEMENT OF PROBLEM. Proper proximal contact is important for maintaining and stabilizing the dental arch. However, the proximal contact strength (PCS) is not a constant value and can be affected by a variety of factors. PURPOSE. This study examined the influences of postural changes on the posterior PCS. MATERIAL AND METHODS. Twelve adults with a normal occlusion and had not undergone prosthetic treatment or proximal restoration were participated in this study. A metal strip was inserted into the proximal surface and removed at a constant velocity. The contact strength was measured in every contact point between canine to second molar in both arches. The PCSs were obtained initially in the upright position, secondly in the supine position and finally in the upright position again. All measurements were repeated after a 2 hour period. Statistical analysis was carried out using the Friedman test (P < .05). RESULTS. Generally, a decrease in PCS occurred when the posture was changed from the initial upright to supine position, while it increased when the posture was changed from the supine to upright position. A significant change was observed in all areas except for between the canine-first premolar in the maxilla and between the first molar-second molar in the mandible areas. CONCLUSION. The posterior PCS, which dentists generally believe to be a static feature of occlusion, is affected significantly by posture.

A research study on the necessity of school oral health education (학교구강보건교육의 필요성에 관한 조사 연구)

  • Kwag, Jung-Suk;Woo, Seung-Hee;Kim, Eun-Ju
    • Journal of Korean Dental Hygiene Science
    • /
    • v.1 no.1
    • /
    • pp.47-55
    • /
    • 2018
  • The purpose of this study was to examine the influence of oral health education experience on needs for oral health education in children and adolescents in elementary and secondary schools. A self-administered survey was conducted on the students in elementary, middle and high schools located in the city of Mokpo, South Jeolla Province, from October 1 to 31, 2018. The data that were collected from 327 students were analyzed by SPSS 21.0. Statistical data on frequency, percentage, mean and standard deviation were obtained, and t-test, one-way ANOVA, correlation analysis and logistic regression analysis were carried out. The findings of the study were as follows: First, the subjects got 2.25 on a three-point scale in self-rated oral health status. This score was above average, which indicated that the students thought they were in good oral health. As for problems with oral health, dental caries was given the highest score of 2.48 on a five-point scale, followed by oral malodor with 2.35. Second, the students who experienced oral health education accounted for 69.1 percent, and the students who felt the need for this education represented 82.6 percent. As for educational content desired, the biggest group of 57.8 percent hoped to learn about how to prevent and manage dental caries, and the second largest group of 17 percent wanted to learn about how to take care of oral health during orthodontic treatment. Third, as a result of investigating the state of oral health education by the grade of school, the elementary school students had more oral health education experience than the middle and high school students, and the middle school students placed the most importance on the necessity of oral health education. The differences were statistically significant. Fourth, as a result of analyzing the correlation between oral health education experience and the necessity of oral health education, the students who had more oral health education experience asked more for this education, which implies that there was a statistically significant positive correlation. The findings of the study ascertained that oral health education should be provided for students in childhood and adolescence to boost the level of their oral health knowledge and change their oral health attitude in a positive manner. If oral health practice programs that connect schools, local communities and families with one another are developed to guide the oral health behaviors of teenagers in the right direction, it will make a contribution to the promotion of oral health.

Changes of lip morphology following mandibular setback surgery using 3D cone-beam computed tomography images

  • Paek, Seung Jae;Yoo, Ji Yong;Lee, Jang Won;Park, Won-Jong;Chee, Young Deok;Choi, Moon Gi;Choi, Eun Joo;Kwon, Kyung-Hwan
    • Maxillofacial Plastic and Reconstructive Surgery
    • /
    • v.38
    • /
    • pp.38.1-38.10
    • /
    • 2016
  • Background: The aims of this study are to evaluate the lip morphology and change of lip commissure after mandibular setback surgery (MSS) for class III patients and analyze association between the amount of mandibular setback and change of lip morphology. Methods: The samples consisted of 14 class III patients treated with MSS using bilateral sagittal split ramus osteotomy. Lateral cephalogram and cone-beam CT were taken before and about 6 months after MSS. Changes in landmarks and variables were measured with 3D software program $Ondemand^{TM}$. Paired and independent t tests were performed for statistical analysis. Results: Landmarks in the mouth corner (cheilion, Ch) moved backward and downward (p < .005, p < .01). However, cheilion width was not statistically significantly changed. Landmark in labrale superius (Ls) was not altered significantly. Upper lip prominence angle (ChRt-Ls-$ChLt^{\circ}$) became acute. Landmarks in stomion (Stm), labrale inferius (Li) moved backward (p < .005, p < .001). Lower lip prominence angle (ChRt-Li-$ChLt^{\circ}$) became obtuse (p < .001). Height of the upper and lower lips was not altered significantly. Length of the upper lip vermilion was increased (p =< 0.01), and length of the lower lip vermilion was decreased (p < .05). Lip area on frontal view was not statistically significantly changed, but the upper lip area on lateral view was increased and change of the lower lip area decreased (p > .05, p < .005). On lateral view, upper lip prominent point (UP) moved downward and stomion moved backward and upward and the angle of Ls-UP-Stm ($^{\circ}$) was decreased. Lower lip prominent point (LP) moved backward and downward, and the angle of Stm-LP-Li ($^{\circ}$) was increased. Li moved backward. Finally, landmarks in the lower incisor tip (L1) moved backward and upward, but stomion moved downward. After surgery, lower incisor tip (L1) was positioned more superiorly than stomion (p < .05). There were significant associations between horizontal soft tissue and corresponding hard tissue. The posterior movement of L1 was related to statistically significantly about backward and downward movement of cheilion. Conclusions: The lip morphology of patients with dento-skeletal class III malocclusion shows a significant improvement after orthognathic surgery. Three-dimensional lip morphology changes in class III patients after MSS exhibited that cheilion moved backward and downward, upper lip projection angle became acute, lower lip projection angle became obtuse, change of upper lip area on lateral view was increased, change of lower lip area decreased, and morphology of lower lip was protruding. L1 was concerned with the lip tissue change in statistically significant way.

Dynamic Analysis of CRM Strategy for Online Shopping-mall (온라인쇼핑몰의 CRM 전략에 관한 동태적 분석: System Dynamics 기법을 활용한 고객만족도 분석을 중심으로)

  • Kang, Jae-Won;Lim, Jay-Ick;Lee, Sang-Gun
    • Information Systems Review
    • /
    • v.9 no.3
    • /
    • pp.99-132
    • /
    • 2007
  • As customer management rises by important issue in electronic commerce, virtue study about CRM have proceeded much. However, because existent researches were positive researches of most statistical base, There are some limitation that does not show dynamic change with CRM flow by flowing of time, and can not forecast propriety and future result about CRM strategy. Therefore, in order to overcome existent limitation on these CRM study, this study designed dynamic model which draws factors that compose CRM strategy of on-line shopping mall, and do based on technique in system dynamics so that can analyze dynamic change between these factors. Concretely, atomized customer focuses in the on-line shopping mall and does based on Permission marketing theory, and applied CRM of different level to atomized customers and know change of customer satisfaction measurement and discomfort degree accordingly. According to the result of Simulation practice, situation that achieve CRM strategy of different level by atomize customer more increase the customer satisfaction than situation that is not so. Dynamic pattern that presented in this study is expected that can verify validity about CRM achievement strategy of different level at each CRM point of contact & how Internet enterprise including on-line shopping mall is establishing CRM strategy reasonably.