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Characteristics of Coal Devolatilization and Spontaneous Combustion at Low Temperatures (저온영역에서 석탄의 탈휘발 및 자연발화 특성 연구)

  • Sung Min Yoon;Seok Hyeong Lee;Tae Hwi An;Myung Won Seo;Sang Won Lee;Dae Sung Kim;Tae-Young Mun;Sung Jin Park;Sang Jun Yoon;Ji Hong Moon;Jae Goo Lee;Jong Hoon Joo;Ho Won Ra
    • Clean Technology
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    • v.29 no.4
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    • pp.288-296
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    • 2023
  • Coal is abundantly available compared to other energy sources and is used as a versatile energy resource worldwide. To address the environmental issues stemming from conventional coal utilization, efforts are underway to develop clean coal utilization technologies, with IGCC technology being a notable example. In IGCC plants, coal is subjected to a CMD process where both drying and pulverization are achieved by supplying hot air. However, if the temperature of the supplied hot air is excessively high, it can lead to devolatilization and spontaneous combustion, thereby compromising the stable operation of the CMD process. This study aimed to measure the devolatilization and spontaneous combustion temperatures of different types of bituminous coal, and to explore their correlations with the characteristics of the coals. Six coal types exhibited devolatilization between 350 and 400 ℃, while three coal types showed devolatilization at temperatures exceeding 400 ℃. Spontaneous combustion ℃curred in one coal type below 100 ℃, six coal types between 100 and 150 ℃, and two coal types above 150 ℃. The measured initiation temperatures were compared with the coal characteristics including the oxygen, moisture, Fe2O3, and CaO content, the H/C ratio, and the O/C ratio to establish correlations. Regression analysis was used to calculate the regression coefficients and determination coefficients for each ignition temperature. It was found that 52.44% of the FC/VM data significantly influenced the volatile matter ignition temperature, and 59.10% of the Fe2O3 data significantly affected the spontaneous combustionignition temperature.

The Effect of Social Entrepreneurship on Entrepreneurial Motivation and Intention in Social Enterprises (사회적 기업가정신 및 창업동기가 창업의지에 미치는 영향)

  • Chung, Young-Soo;Jung, Chul-Ho
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.3
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    • pp.115-125
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    • 2023
  • The purpose of this study is to empirically identify the influence of social entrepreneurship on the formation of entrepreneurial motivation and entrepreneurial intention. In order to effectively achieve the purpose of the study, a research model and hypotheses are developed based on the results of a comprehensive review of relevant prior literature. The research model is set as social entrepreneurship including innovativeness, risk-taking, initiative, and social value orientation as independent variables, and entrepreneurship motivation is divided into intrinsic and extrinsic motivation. For the study, data were collected from a total of 114 social enterprise-related prospective entrepreneurs and early start-ups, and a research model and hypotheses analysis are conducted. The results of the empirical analysis are summarized as follows. First, all four components of social entrepreneurship were found to have a positive effect on intrinsic motivation. However, it is found that innovativeness and initiative among the components of social entrepreneurship has a positive effect on extrinsic motivation, whereas risk-taking and social value orientation has no significant effect on extrinsic motivation. Second, all four components of social entrepreneurship were found to have a positive effect on the entrepreneurial intention. Third, both intrinsic and extrinsic entrepreneurial motivation are found to have a positive effect on entrepreneurial intention. Finally, in the relationship between social entrepreneurship and entrepreneurial intention, both intrinsic and extrinsic entrepreneurial motivation are confirmed to have a positive mediating effect. This study specified the factors of social entrepreneurship and entrepreneurship motivation that affect entrepreneurship awareness and behavior targeting social enterprises with differentiated characteristics from existing for-profit enterprises. And through an empirical analysis of the influence relationship between these factors, an attempt was made to derive academic and practical implications.

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Investment Priorities and Weight Differences of Impact Investors (임팩트 투자자의 투자 우선순위와 비중 차이에 관한 연구)

  • Yoo, Sung Ho;Hwangbo, Yun
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.3
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    • pp.17-32
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    • 2023
  • In recent years, the need for social ventures that aim to grow while solving social problems through the efficiency and effectiveness of commercial organizations in the market has increased, while there is a limit to how much the government and the public can do to solve social problems. Against this background, the number of social venture startups is increasing in the domestic startup ecosystem, and interest in impact investors, which are investors in social ventures, is also increasing. Therefore, this research utilized judgment analysis technology to objectively analyze the validity and weight of judgment information based on the cognitive process and decision-making environment in the investment decision-making of impact investors. We proceeded with the research by constructing three classifications; first, investment priorities at the initial investment stage for financial benefit and return on investment as an investor, second, the political skills of the entrepreneurs (teams) for the social impact and ripple power, and social venture coexistence and solidarity, third, the social mission of a social venture that meets the purpose of an impact investment fund. As a result of this research, first of all, the investment decision-making priorities of impact investors are the expertise of the entrepreneur (team), the potential rate of return when the entrepreneur (team) succeeds, and the social mission of the entrepreneur (team). Second, impact investors do not have a uniform understanding of the investment decision-making factors, and the factors that determine investment decisions are different, and there are differences in the degree of the weighting. Third, among the various investment decision-making factors of impact investment, "entrepreneur's (team's) networking ability", "entrepreneur's (team's) social insight", "entrepreneur's (team's) interpersonal influence" was relatively lower than the other four factors. The practical contribution through this research is to help social ventures understand the investment determinant factors of impact investors in the process of financing, and impact investors can be expected to improve the quality of investment decision-making by referring to the judgment cases and analysis of impact investors. The academic contribution is that it empirically investigated the investment priorities and weighting differences of impact investors.

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The Effects of Luck in Belief and Positive Cognitive Bias on Entrepreneurial Self-Efficacy (행운신념이 긍정적 인지편향과 창업효능감에 미치는 영향)

  • Ha, Hwan Ho;Byun, Chung Gyu
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.18 no.5
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    • pp.33-44
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    • 2023
  • Entrepreneurial self-efficacy is an important variable that explains people's attitudes and behaviors toward start-ups. In this study, we focused on individual psychological characteristics variables such as luck in belief and positive cognitive bias that affect entrepreneurial self-efficacy. Among these variables, we paid particular attention to luck in belief. The belief that business success depends on luck is widespread, but scientific verification about it has not been much. The reason for the academic indifference is that luck is a kind of superstition, related to precognition or extrasensory perception, and randomly caused by the external environment. The study of luck began in earnest as a measure to measure luck as an individual characteristic variable such as personality was developed. The purpose of this study is to examine the existing studies on luck in belief and to examine the effect of this luck in belief on positive cognitive bias and entrepreneurial self-efficacy through empirical analysis. For empirical analysis, this study conducted an on-line survey of 400 ordinary people and conducted a structural equation model analysis using AMOS 21.0 to verify the hypothesis. As a result of hypothesis testing, all hypotheses that luck in belief would have a positive effect on positive cognitive bias(self-enhancement bias, illusion of control bias, unrealism optimistic bias) were adopted. The hypothesis that positive cognitive bias(self-enhancement bias, illusion of control bias, unrealistic optimism bias) will have a positive effect on entrepreneurial self-efficacy was also adopted. Additional analysis was conducted to examine the mediating role of positive cognitive bias in the relationship between luck in belief and entrepreneurial self-efficacy, which showed that 'luck in belief→positive cognitive bias →entrepreneurial self-efficacy' were statistically significant. Through this, we confirmed the mediating effect of positive cognitive bias in the relationship between luck in belief and entrepreneurial self-efficacy. In the conclusion, the implications and limitations of the study were presented based on the results of this study.

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A Study on the Effects of Entrepreneurial Marketing Orientation on the Management Performance: Mediated Effect of Organizational Marketing Capabilities (창업자의 앙트레프레니얼 마케팅 지향성이 경영성과에 미치는 영향: 조직내 마케팅역량의 매개효과)

  • Byun, Hong Joo;Byun, Chung Gyu;Ha, Hwan Ho
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.4
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    • pp.87-100
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    • 2022
  • Early start-up companies have an inherent limitation of lack of resources. Despite these limitations, in order to survive, the entrepreneur's personal ability to efficiently use limited resources is required. In the marketing field, various studies are needed to reduce the business failure rate through establishing growth strategies and innovation. Accordingly, it is necessary to apply the concept of entrepreneurial marketing, which has been researched and developed overseas for 30 years, to fit the domestic reality. According to the flow of this study, an empirical study should be preceded to clarify the influence relationship between entrepreneurial marketing orientation, marketing competency, and management performance, along with a theoretical theorem on entrepreneurial marketing that is suitable for early start-ups and small and medium-sized enterprises(SMEs) and can respond innovatively to changes. The establishment of entrepreneurial marketing orientation and the processes from which this concept leads to business performance through the organization's marketing capabilities and its effects will be empirically verified. For an empirical survey, a survey was conducted on founders of 220 companies, and path analysis using structural equations was used for hypothesis verification. The findings are as follows. First, it was found that the entrepreneurial marketing orientation had a positive effect on both the organization's marketing capabilities and management performance. Second, it was found that the organization's marketing capabilities also had a positive effect on management performance. Third, as a result of empirical analysis of the mediating effect of the organization's marketing capabilities on the relationship between entrepreneurial marketing orientation and management performance, it was found that marketing capabilities showed a greater mediating effect on non-financial performance than financial performance. On the other hand, it was confirmed that marketing performance had a stronger mediating effect on financial performance than non-financial performance. By confirming and presenting the concept and constituent factors of entrepreneurial marketing orientation of domestic start-ups, which were academic gaps for the purpose of this paper, the academic research is differentiated in that they were verified as six components of entrepreneurial marketing. The practical implications of the research results will be that the entrepreneurial marketing-oriented mindset of small and medium-sized companies will optimize market analysis capabilities, network with various stakeholders, and increase the organization's ability to demonstrate marketing capabilities.

An Analysis on the Level of Evidence used in Gifted Elementary Students' Debate (초등과학 영재의 논증활동에서 사용된 증거의 수준 분석)

  • Cho, Hyun-Jun;Yang, Il-Ho;Lee, Hyo-Nyong;Song, Yun-Mi
    • Journal of The Korean Association For Science Education
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    • v.28 no.5
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    • pp.495-505
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    • 2008
  • The purpose of this study was to analyze the level of evidence used in gifted elementary students' argumentation. The subjects were 15, 5th and 6th grade students selected in the Science Education Institute for Gifted Youth in K University. After the argumentation task was given to students 2 weeks ago, the students grouped themselves in the affirmative and negative and took part in a debate for 2 hours. Their argumentation process was observed, recorded and transcribed for analysis. Transcribed data was given a Protocol Number according to priority and was examined to find out what were the characteristics when students participated in the task. The evidence used in argumentation was graded from level 1 to level 6 according to Perella's Hierarchy of Evidence and the rate of frequency classified by the level was expressed in graph. Students used Level 1- Level 2 evidence above 50% without for or against task. They had weak argumentation making use of low-level evidence such as individual experience, opinion and another person's experience rather than objective evidences. On the other hand, students commented on the lack of opponent's evidence when they could not trust an opponent's evidence. If one team asked the other to present more evidence but could not, they disregarded the question and turned to another topic. And in cases where the opponent team refuted with evidences of high level, the other team just repeated their claim or evaded the rebuttal. The students tended to complete the argument without the same conclusions with some interruptions. The results show that we need an educational programs including scientific argumentation for science-gifted elementary school students.

Korean Clinical Imaging Guidelines for the Appropriate Use of Chest MRI (한국형 흉부 MRI 영상 진단 정당성 권고안)

  • Jiyoung Song;Bo Da Nam;Soon Ho Yoon;Jin Young Yoo;Yeon Joo Jeong;Chang Dong Yeo;Seong Yong Lim;Sung Yong Lee;Hyun Koo Kim;Byoung Hyuck Kim;Kwang Nam Jin;Hwan Seok Yong
    • Journal of the Korean Society of Radiology
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    • v.82 no.3
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    • pp.562-574
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    • 2021
  • MRI has the advantages of having excellent soft-tissue contrast and providing functional information without any harmful ionizing radiation. Although previous technical limitations restricted the use of chest MRI, recent technological advances and expansion of insurance coverage are increasing the demand for chest MRI. Recognizing the need for guidelines on appropriate use of chest MRI in Korean clinical settings, the Korean Society of Radiology has composed a development committee, working committee, and advisory committee to develop Korean chest MRI justification guidelines. Five key questions were selected and recommendations have been made with the evidence-based clinical imaging guideline adaptation methodology. Recommendations are as follows. Chest MRI can be considered in the following circumstances: for patients with incidentally found anterior mediastinal masses to exclude non-neoplastic conditions, for pneumoconiosis patients with lung masses to differentiate progressive massive fibrosis from lung cancer, and when invasion of the chest wall, vertebrae, diaphragm, or major vessels by malignant pleural mesothelioma or non-small cell lung cancer is suspected. Chest MRI without contrast enhancement or with minimal dose low-risk contrast media can be considered for pregnant women with suspected pulmonary embolism. Lastly, chest MRI is recommended for patients with pancoast tumors planned for radical surgery.

Construction of a Standard Dataset for Liver Tumors for Testing the Performance and Safety of Artificial Intelligence-Based Clinical Decision Support Systems (인공지능 기반 임상의학 결정 지원 시스템 의료기기의 성능 및 안전성 검증을 위한 간 종양 표준 데이터셋 구축)

  • Seung-seob Kim;Dong Ho Lee;Min Woo Lee;So Yeon Kim;Jaeseung Shin;Jin‑Young Choi;Byoung Wook Choi
    • Journal of the Korean Society of Radiology
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    • v.82 no.5
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    • pp.1196-1206
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    • 2021
  • Purpose To construct a standard dataset of contrast-enhanced CT images of liver tumors to test the performance and safety of artificial intelligence (AI)-based algorithms for clinical decision support systems (CDSSs). Materials and Methods A consensus group of medical experts in gastrointestinal radiology from four national tertiary institutions discussed the conditions to be included in a standard dataset. Seventy-five cases of hepatocellular carcinoma, 75 cases of metastasis, and 30-50 cases of benign lesions were retrieved from each institution, and the final dataset consisted of 300 cases of hepatocellular carcinoma, 300 cases of metastasis, and 183 cases of benign lesions. Only pathologically confirmed cases of hepatocellular carcinomas and metastases were enrolled. The medical experts retrieved the medical records of the patients and manually labeled the CT images. The CT images were saved as Digital Imaging and Communications in Medicine (DICOM) files. Results The medical experts in gastrointestinal radiology constructed the standard dataset of contrast-enhanced CT images for 783 cases of liver tumors. The performance and safety of the AI algorithm can be evaluated by calculating the sensitivity and specificity for detecting and characterizing the lesions. Conclusion The constructed standard dataset can be utilized for evaluating the machine-learning-based AI algorithm for CDSS.

Effect of Service Convenience on the Relationship Performance in B2B Markets: Mediating Effect of Relationship Factors (B2B 시장에서의 서비스 편의성이 관계성과에 미치는 영향 : 관계적 요인의 매개효과 분석)

  • Han, Sang-Lin;Lee, Seong-Ho
    • Journal of Distribution Research
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    • v.16 no.4
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    • pp.65-93
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    • 2011
  • As relationship between buyer and seller has been brought closer and long-term relationship has been more important in B2B markets, the importance of service and service convenience increases as well as product. In homogeneous markets, where service offerings are similar and therefore not key competitive differentiator, providing greater convenience may enable a competitive advantage. Service convenience, as conceptualized by Berry et al. (2002), is defined as the consumers' time and effort perceptions related to buying or using a service. For this reason, B2B customers are interested in how fast the service is provided and how much save non-monetary cost like time or effort by the service convenience along with service quality. Therefore, this study attempts to investigate the impact of service convenience on relationship factors such as relationship satisfaction, relationship commitment, and relationship performance. The purpose of this study is to find out whether service convenience can be a new antecedent of relationship quality and relationship performance. In addition, this study tries to examine how five-dimensional service convenience constructs (decision convenience, access convenience, transaction convenience, benefit convenience, post-benefit convenience) affect customers' relationship satisfaction, relationship commitment, and relationship performance. The service convenience comprises five fundamental components - decision convenience (the perceived time and effort costs associated with service purchase or use decisions), access convenience(the perceived time and effort costs associated with initiating service delivery), transaction convenience(the perceived time and effort costs associated with finalizing the transaction), benefit convenience(the perceived time and effort costs associated with experiencing the core benefits of the offering) and post-benefit convenience (the perceived time and effort costs associated with reestablishing subsequent contact with the firm). Earlier studies of perceived service convenience in the industrial market are none. The conventional studies that have dealt with service convenience have usually been made in the consumer market, or they have dealt with convenience aspects in the service process. This service convenience measure for consumer market can be useful tool to estimate service quality in B2B market. The conceptualization developed by Berry et al. (2002) reflects a multistage, experiential consumption process in which evaluations of convenience vary at each stage. For this reason, the service convenience measure is good for B2B service environment which has complex processes and various types. Especially when categorizing B2B service as sequential stage of service delivery like Kumar and Kumar (2004), the Berry's service convenience measure which reflect sequential flow of service deliveries suitable to establish B2B service convenience. For this study, data were gathered from respondents who often buy business service and analyzed by structural equation modeling. The sample size in the present study is 119. Composite reliability values and average variance extracted values were examined for each variable to have reliability. We determine whether the measurement model supports the convergent validity by CFA, and discriminant validity was assessed by examining the correlation matrix of the constructs. For each pair of constructs, the square root of the average variance extracted exceeded their correlations, thus supporting the discriminant validity of the constructs. Hypotheses were tested using the Smart PLS 2.0 and we calculated the PLS path values and followed with a bootstrap re-sampling method to test the hypotheses. Among the five dimensional service convenience constructs, four constructs (decision convenience, transaction convenience, benefit convenience, post-benefit convenience) affected customers' positive relationship satisfaction, relationship commitment, and relationship performance. This result means that service convenience is important cue to improve relationship between buyer and seller. One of the five service convenience dimensions, access convenience, does not affect relationship quality and performance, which implies that the dimension of service convenience is not important factor of cumulative satisfaction. The Cumulative satisfaction can be distinguished from transaction-specific customer satisfaction, which is an immediate post-purchase evaluative judgment or an affective reaction to the most recent transactional experience with the firm. Because access convenience minimizes the physical effort associated with initiating an exchange, the effect on relationship satisfaction similar to cumulative satisfaction may be relatively low in terms of importance than transaction-specific customer satisfaction. Also, B2B firms focus on service quality, price, benefit, follow-up service and so on than convenience of time or place in service because it is relatively difficult to change existing transaction partners in B2B market compared to consumer market. In addition, this study using partial least squares methods reveals that customers' satisfaction and commitment toward relationship has mediating role between the service convenience and relationship performance. The result shows that management and investment to improve service convenience make customers' positive relationship satisfaction, and then the positive relationship satisfaction can enhance the relationship commitment and relationship performance. And to conclude, service convenience management is an important part of successful relationship performance management, and the service convenience is an important antecedent of relationship between buyer and seller such as the relationship commitment and relationship performance. Therefore, it has more important to improve relationship performance that service providers enhance service convenience although competitive service development or service quality improvement is important. Given the pressure to provide increased convenience, it is not surprising that organizations have made significant investments in enhancing the convenience aspect of their product and service offering.

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A Survey on the Perception of the Counterplans of Medical Accident and Dispute of Dental Hygienist (의료사고 및 의료분쟁에 대한 치위생사의 인식도 조사)

  • Oh, Jin-Ho;Kwon, Jeong-Seung;Ahn, Hyoung-Joon;Kang, Jin-Kyu;Choi, Jong-Hoon
    • Journal of Oral Medicine and Pain
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    • v.32 no.1
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    • pp.9-33
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    • 2007
  • In the field of dentistry, there existed relatively few emergency patients or patients who need intensive care and thus had low medical dispute rates. However, these days, there is a general tendency of increased medical disputes. Although many medical disputes are caused by medical accidents of the dentists, because dental assistants are also lawfully involved in practicing dentistry, there is a possibility of medical disputes or medical accidents caused by dental assistants. Therefore, the role of the dental assistants cannot be ignored. This study consists of a survey given to dental hygienists currently working in general hospitals, dental hospitals and private dental clinics. Following is the results of the analysis of 275 respondents' backgrounds, medical disputes rates including patients' complaints, their understanding of medical regulations and their general understanding of overall dental practice and medical disputes. 1. 251 of 274(91.6%) respondents doubted the risk of medical accident and dispute. 2. 81(29.5%) dental hygienist experienced complaint from patients. They have been working in the private dental clinic, the rate of this experience was high. 3. 349 case of 1805(19.3%) the complaints by patients, highest percentage among its category, were those regarding dental fees and poor service. 4. 129 case of 1805(7.1%) patients' complaints, highest percentage among it's subcategory, were those regarding the absence of explanations of precautions or request of agreements before dental treatment. 5. 252 of 267 (94.4%) dental hygienists chart after a scaling treatment. However, only 55(20.7%) dental hygienists chart the fact of explaining the precautions. 6. 6(2.2%) dental hygienists do not inspect patients' medical history, if patients don't mention it. 7. 104 of 274(38.0%) dental hygienists responded to be capable of administering first aid treatment. 8. 115(41.8%) dental hygienists have a first aid kit and equipment. 9. In case of medical dispute, 268(97.8%) dental hygienists respond that, charting plays a big role in resolving the dispute. 10. In case of medical dispute, 272(93.3%) dental hygienists respond that, explanation and agreement before treatment have an important role in settlement of dispute 11. Only 160(58.4%) dental hygienists responded correct answer that the duration of keeping medical records is 10 years. 12. 124(45.3%) respondents thought that it is legal for a dental hygienist to take a panoramic dental X-ray, 71(25.9%) respondents thought that it is legal practice cervical resin treatment by dental hygienist, and 37(13.5%) respondents thought that it is legal extract primary teeth by dental hygienist. 13. 24(18.76%) respondents thought that it doesn't matter to tell patient's state to others 14. 272(99.27%) responded that receiving education for the prevention of medical disputes was needed and of them, 61.0% thought it was urgent. 15. 186(64.2%) has never had classes regarding the prevention of medical disputes while in school and 212(77.4%) has not had the same type of classes after graduating from school. 16. 256(93.4%) responded that there will be even more of an increased number of medical disputes. Among them, 83.3% of respondents though that due to the increased opportunity of acquiring information through the internet and mass media. The study shows that 29.5 percentage of dental hygienists have experienced the medical disputes and complaints and they are lack of recognition of medical regulations and dental hygienist's official duty. So, there is a big potential of the percentage to increase. Therefore, the correct understanding of explaining precautions and requesting agreement before dental treatments and performing them are mandatory. Moreover, classes regarding the prevention and counterplans of medical disputes need to be widely offered.