• Title/Summary/Keyword: importance sampling (IS)

Search Result 314, Processing Time 0.032 seconds

Recognition of Good Death, Attitude towards the Withdrawal of Life-Sustaining Treatment, and Attitude towards Euthanasia in Nurses (좋은 죽음에 대한 인식, 연명치료 중단 및 안락사에 대한 종합병원 간호사의 태도)

  • Kim, Sook-Nam;Kim, Hyun-Ju
    • Journal of Hospice and Palliative Care
    • /
    • v.19 no.2
    • /
    • pp.136-144
    • /
    • 2016
  • Purpose: To provide practical data for bioethics education, we identified correlations between recognition of good death, attitude towards withdrawal of meaningless life-sustaining treatment, and attitude towards euthanasia in nurses. Methods: Using convenience sampling, we recruited 218 nurses who had at least six-month work experience in one of the six general hospitals with 500 or more beds in Seoul, Busan, and Gyeongsang province. All participants understood the purpose of the study and agreed to take part in the study. The research tools used included the Concept of Good Death Measure (CoGD), the measurement tool for attitudes towards withdrawal of meaningless life-sustaining treatment (WoMLST), and the measurement tool for attitudes towards euthanasia. Data were analyzed using an Independent t-test, one-way ANOVA, and Pearson's correlation coefficient using SPSS 21 for Windows. Results: Nurses had normal levels on CoGD, WoMLST, and attitudes towards euthanasia. Nurses' CoGD, WoMLST, and euthanasia scores significantly differed depending on their education level, working period, and the importance of religion to them. A negative correlation was found between the CoGD and WoMLST scores, and WoMLST and euthanasia scores were positively correlated. Conclusion: Nurses should be trained to deal with ethical issues that may arise while caring for terminal patients. It is necessary for nurses to understand the concepts related to CoGD, WoMLST, and euthanasia, and to promote bioethics education with focus on decision-making and problem-solving ability in ethically conflicting situations.

Utilization of Work-Family Balance Support Policy and Factors Associated with Retention Intention among Married Female Officers with Preschool Children (미취학 자녀를 둔 기혼 여군 장교의 일·가정 양립 지원제도 활용 정도와 재직의도 영향요인)

  • Kwon, Jo Eun;Kim, Gwang Suk;Park, Jeongok;Kim, Sue
    • Women's Health Nursing
    • /
    • v.25 no.3
    • /
    • pp.329-344
    • /
    • 2019
  • Purpose: This study aimed to identify utilization of the work-family support policy (WFSP) and factors affecting retention intention among Korean female military officers. Methods: This cross-sectional survey recruited 103 married female officers from the Korean Army, Navy, and Air force with preschool-aged children through convenience and snowball sampling. Via online surveys from June to November, 2018, the participants self-reported retention intention, work-family conflict, job satisfaction, and utilization of the WFSP. The data were analyzed using descriptive statistics, independent t-tests, one-way analysis of variance, Pearson's correlation coefficient, and multiple linear regression. Results: Retention intention ($22.29{\pm}5.98$) was reported at the mid-level, lower than scores reported in the literature for female workers. Work-family conflict ($32.51{\pm}5.29$) and job satisfaction ($63.10{\pm}7.45$) were above the midpoint levels. Use of maternity leave (100.0%) and parental leave (92.2%) was high, especially compared to the rates of child-care day off (20.4%) and parenting time (20.4%). 'Noticeable increases in childcare services within the army' (22.8%) was reported as the supportive measure needed the most by female military officers. Job satisfaction (${\beta}=.43$, $p{\leq}.001$), the use of parenting time (${\beta}=-0.29$, p=.002), living type (${\beta}=-.18$, p=.043), and service type (${\beta}=-.16$, p=.035) significantly influenced retention intention. Conclusions: The findings highlight the priority areas of importance within the WFSP and suggest that a family-friendly culture can improve female officers' retention intention. Accordingly, policy changes at the Ministry of National Defense improving the system to enhance a family-friendly culture in the military is expected to strengthen the retention intention of female officers and contribute to excellence in the military workforce.

Polycyclic Aromatic Hydrocarbons in Industrial Organic Sludge from Wastewater Treatment Facilities in Korea (폐수처리시설에서 발생된 유기성 슬러지에 함유된 다환방향족탄화수소의 농도 특성)

  • Nam, Seong-Nam;Lee, Mi-Young;Yeon, Jinmo;Jeon, Taewan;Shin, Sun Kyoung
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.34 no.8
    • /
    • pp.574-582
    • /
    • 2012
  • This study presents the concentrations of the polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by United States Environmental Protection Agency (US EPA), in 98 sludges from 54 industrial wastewater treatment facilities of South Korea. The mean concentrations of ${\Sigma}_{16}PAHs$ were ranged from 32.5 ${\mu}g/kg-dw$ to 1189.3 ${\mu}g/kg-dw$ by industries, and the highest content was found in the petrochemical industry, followed by chemical, clothing manufacturing and dying, pulp and papermaking, secondary wastewater treatment, and food/beverage producing industries. Comparisons to the EU and Danish standards of ${\Sigma}_{16}PAHs$ in sewage sludge for land application showed only two samples (one from petrochemical, and the other from chemical industry) exceeded the limits. ANOVA test with PAH concentrations as variables revealed no statistically significant influences by industrial types and sampling time (i.e., seasonal variations). Pearson correlations between individual PAHs showed strong relationships (r>0.7) among 4-ring PAHs. Concentrations of acenaphthylene, anthracene, fluoranthene, benzo(a)anthracene, benzo(f)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene presented strong correlations to ${\Sigma}_{16}PAHs$. Principal component analysis discriminated entire samples into three groups by two principal components (PC1 and PC2) with 70% of data variations, in which industrial types were not of importance, but a dominance of certain PAHs. Samples in group-I, which is high PC1 and low PC2, were characterized by a dominance of 2-ring PAHs, and in group-II, PC1 and PC2 showed a linear relation, was dominant 4-ring PAHs. Group-III with low PC1 and high PC2 includes 17 samples showing a noticeably high contribution of 3-ring PAHs to ${\Sigma}_{16}PAHs$. This study provides concentrations of PAHs in industrial sludges collected from a wide variety of sources (six industrial types) and two seasons of sampling events, and the comparison of ${\Sigma}_{16}PAHs$ with other studies are also discussed.

Study on the screening method for determination of heavy metals in cellular phone for the restrictions on the use of certain hazardous substances (RoHS) (유해물질 규제법(RoHS)에 따른 휴대폰 내의 중금속 함유량 측정을 위한 스크리닝법 연구)

  • Kim, Y.H.;Lee, J.S.;Lim, H.B.
    • Analytical Science and Technology
    • /
    • v.23 no.1
    • /
    • pp.1-14
    • /
    • 2010
  • It is of importance that all countries in worldwide, including EU and China, have adopted the Restrictions on the use of certain Hazardous Substances (RoHS) for all electronics. IEC62321 document, which was published by the International Electronics Committee (IEC) can have conflicts with the standards in the market. On the contrary Publicly Accessible Specification (PAS) for sampling published by IEC TC111 can be adopted for complementary application. In this work, we tried to find a route to disassemble and disjoint cellular phone sample, based on PAS and compare the screening methods available in the market. For this work, the cellular phone produced in 2001, before the regulation was born, was chosen for better detection. Although X-ray Fluorescence (XRF) showed excellent performance for screening, fast and easy handling, it can give information on the surface, not the bulk, and have some limitations due to significant matrix interference and lack of variety of standards for quantification. It means that screening with XRF sometimes requires supplementary tool. There are several techniques available in the market of analytical instruments. Laser ablation (LA) ICP-MS, energy dispersive (ED) XRF and scanning electron microscope (SEM)-energy dispersive X-ray (EDX) were demonstrated for screening a cellular phone. For quantitative determination, graphite furnace atomic absorption spectrometry (GF-AAS) was employed. Experimental results for Pb in a battery showed large difference in analytical results in between XRF and GF-AAS, i.e., 0.92% and 5.67%, respectively. In addition, the standard deviation of XRF was extremely large in the range of 23-168%, compared with that in the range of 1.9-92.3% for LA-ICP-MS. In conclusion, GF-AAS was required for quantitative analysis although EDX was used for screening. In this work, it was proved that LA-ICP-MS can be used as a screening method for fast analysis to determine hazardous elements in electrical products.

Exploration of the Relationship Structure of Personal and Social Cognitive Factors Affecting Professional Help-seeking Decisions for Distress among People in Low-income (저소득층의 디스트레스에 따른 전문가 도움추구의 결정에 영향을 미치는 개인 및 사회인지 요인들의 관계구조 탐색)

  • Park, Sunyoung
    • Korean Journal of Social Welfare
    • /
    • v.67 no.2
    • /
    • pp.85-112
    • /
    • 2015
  • This study examined the relationship structure among personal and social cognitive factors contributing to professional help-seeking decisions to relieve distress of those in low-income, then suggested an appropriate model to inform knowledge for better social work practice. Using data of a purposive sampling from 331 low-income people, covariance structural analyses were conducted in two stages of model exploration, one for TPB model and another for its extended model including the level of distress, family support, and willingness. As results, in the path analyses with the observed variables of the basic components of the TPB, subjective norm showed the strongest effect on the intention, following by attitudes towards help-seeking, then behavioral control the least; in turn both the intention, positively, and behavioral control, negatively, contributed to help-seeking decisions. In the second stage of the path analyses with the extended model of the TPB, each of distress and family support demonstrated direct positive effect on each of attitudes, subjective norm, and behavioral control; each of the attitudes, subjective norm, and behavioral control showed positive effect on both intention and willingness; in turn, while intention showed strong positive effect on help-seeking decisions, willingness had no significant effect and behavioral control had negative effect on decisions. There were significant indirect effects of behavioral control on intention through willingness and of willingness on decisions through intention. These results suggested that the TPB model is useful for modeling help-seeking decisions through personal and social cognitions, especially the significance of subjective norm implied the importance of social cognition for the people in low-income with distress. Further, it was implied that the extended model needs to address particularity of those people in low-income and the mechanism shown by behavioral control and willingness implied the importance of practicing respect for the client's autonomy and will for self-support in social work practice.

  • PDF

An Examination of Knowledge Sourcing Strategies Effects on Corporate Performance in Small Enterprises (소규모 기업에 있어서 지식소싱 전략이 기업성과에 미치는 영향 고찰)

  • Choi, Byoung-Gu
    • Asia pacific journal of information systems
    • /
    • v.18 no.4
    • /
    • pp.57-81
    • /
    • 2008
  • Knowledge is an essential strategic weapon for sustaining competitive advantage and is the key determinant for organizational growth. When knowledge is shared and disseminated throughout the organization, it increases an organization's value by providing the ability to respond to new and unusual situations. The growing importance of knowledge as a critical resource has forced executives to pay attention to their organizational knowledge. Organizations are increasingly undertaking knowledge management initiatives and making significant investments. Knowledge sourcing is considered as the first important step in effective knowledge management. Most firms continue to make an effort to realize the benefits of knowledge management by using various knowledge sources effectively. Appropriate knowledge sourcing strategies enable organizations to create, acquire, and access knowledge in a timely manner by reducing search and transfer costs, which result in better firm performance. In response, the knowledge management literature has devoted substantial attention to the analysis of knowledge sourcing strategies. Many studies have categorized knowledge sourcing strategies into intemal- and external-oriented. Internal-oriented sourcing strategy attempts to increase firm performance by integrating knowledge within the boundary of the firm. On the contrary, external-oriented strategy attempts to bring knowledge in from outside sources via either acquisition or imitation, and then to transfer that knowledge across to the organization. However, the extant literature on knowledge sourcing strategies focuses primarily on large organizations. Although many studies have clearly highlighted major differences between large and small firms and the need to adopt different strategies for different firm sizes, scant attention has been given to analyzing how knowledge sourcing strategies affect firm performance in small firms and what are the differences between small and large firms in the patterns of knowledge sourcing strategies adoption. This study attempts to advance the current literature by examining the impact of knowledge sourcing strategies on small firm performance from a holistic perspective. By drawing on knowledge based theory from organization science and complementarity theory from the economics literature, this paper is motivated by the following questions: (1) what are the adoption patterns of different knowledge sourcing strategies in small firms (i,e., what sourcing strategies should be adopted and which sourcing strategies work well together in small firms)?; and (2) what are the performance implications of these adoption patterns? In order to answer the questions, this study developed three hypotheses. First hypothesis based on knowledge based theory is that internal-oriented knowledge sourcing is positively associated with small firm performance. Second hypothesis developed on the basis of knowledge based theory is that external-oriented knowledge sourcing is positively associated with small firm performance. The third one based on complementarity theory is that pursuing both internal- and external-oriented knowledge sourcing simultaneously is negatively or less positively associated with small firm performance. As a sampling frame, 700 firms were identified from the Annual Corporation Report in Korea. Survey questionnaires were mailed to owners or executives who were most erudite about the firm s knowledge sourcing strategies and performance. A total of 188 companies replied, yielding a response rate of 26.8%. Due to incomplete data, 12 responses were eliminated, leaving 176 responses for the final analysis. Since all independent variables were measured using continuous variables, supermodularity function was used to test the hypotheses based on the cross partial derivative of payoff function. The results indicated no significant impact of internal-oriented sourcing strategies while positive impact of external-oriented sourcing strategy on small firm performance. This intriguing result could be explained on the basis of various resource and capital constraints of small firms. Small firms typically have restricted financial and human resources. They do not have enough assets to always develop knowledge internally. Another possible explanation is competency traps or core rigidities. Building up a knowledge base based on internal knowledge creates core competences, but at the same time, excessive internal focused knowledge exploration leads to behaviors blind to other knowledge. Interestingly, this study found that Internal- and external-oriented knowledge sourcing strategies had a substitutive relationship, which was inconsistent with previous studies that suggested complementary relationship between them. This result might be explained using organizational identification theory. Internal organizational members may perceive external knowledge as a threat, and tend to ignore knowledge from external sources because they prefer to maintain their own knowledge, legitimacy, and homogeneous attitudes. Therefore, integrating knowledge from internal and external sources might not be effective, resulting in failure of improvements of firm performance. Another possible explanation is small firms resource and capital constraints and lack of management expertise and absorptive capacity. Although the integration of different knowledge sources is critical, high levels of knowledge sourcing in many areas are quite expensive and so are often unrealistic for small enterprises. This study provides several implications for research as well as practice. First this study extends the existing knowledge by examining the substitutability (and complementarity) of knowledge sourcing strategies. Most prior studies have tended to investigate the independent effects of these strategies on performance without considering their combined impacts. Furthermore, this study tests complementarity based on the productivity approach that has been considered as a definitive test method for complementarity. Second, this study sheds new light on knowledge management research by identifying the relationship between knowledge sourcing strategies and small firm performance. Most current literature has insisted complementary relationship between knowledge sourcing strategies on the basis of data from large firms. Contrary to the conventional wisdom, this study identifies substitutive relationship between knowledge sourcing strategies using data from small firms. Third, implications for practice highlight that managers of small firms should focus on knowledge sourcing from external-oriented strategies. Moreover, adoption of both sourcing strategies simultaneousiy impedes small firm performance.

A study on physical examination of middle school students (중학교 체질검사 실태에 관한 연구)

  • Park, Sung-Hee
    • Journal of the Korean Society of School Health
    • /
    • v.14 no.1
    • /
    • pp.131-143
    • /
    • 2001
  • The primary aim of this dissertation is to contribute to the improvement of methods in physical examination by providing quality information for the current school system and advice for improving status. Present status, controversial points and possible remedies in physical examination were analyzed on a frequency and percentage basis. An $x^2$-test was used to verify the statistics between the results from the examination and each variable. In case of multiple categories of variables, an $x^2$ cs was adopted. Chronological data as well as both total and sampling physical examination data verified the statistics using an $x^2$-test. This thesis is based both on the data from middle school health care specialists in Gyunggi Province and on the analysis of physical examinations reported from local schools to the municipal education agency from 1997 to 1999. The results of the study are as follows: First, according to the survey, only 29.0% of the total schools had their school doctors examine all the students while most of the educational institutions failed to implement the whole process of physical examination on the list. It also turned out that the more students the schools have, the lower the rate of implementation of physical examination by school doctors(p=0.014). Second, the average time a school doctor spends for checkup turned out to be approximately 1.7 minutes per student This means that the quality of the physical examination is not guaranteed in the process. Third, 47.7% of those surveryed say that a dental examination was performed, each taking 21.24 seconds on average. In addition, it shows that some 31.5% wanted to have a task force team for dental checkups at the local health center. Given the fact that dental caries among students is progressively on the rise, the dental health centers that are now set up in some elementary schools should be expanded to cover the whole educational institution in order to raise awareness of the importance of dental care. Fourth, 48.5% of those surveyed say that a comprehensive physical examination should be adopted to promote the health of high schoolers. Since it takes a lot of public funds to implement a comprehensive method, it is essential to make sure that in-depth studies should be based on the frequency and methods of physical examination. Fifth, regarding such diseases among 3rd year middle school students in 1999, statistics shows that there was a slight difference in the prevalence rate of color blindness, and allergic diseases for male students ; and color blindness, hearing disturbance and allergic disease for female students. For those items, however, it is too little to say that there is a significant difference and accordingly it is assumed to be a problem of the measuring process. Sixth, the result of analysis on the sample physical examination and the total physical examination of the year 1999 shows as follows: For male students in the 3rd year of middle school, a slight difference appeared to those students in 11 items including eye problems and eye disease, otitis media, tonsillar hypertrophy, spinal shape, respiratory urinary allergic disease and other abnormal diseases(p<0.05). Particularly, the prevalence rate between students with and without disease was shown to be two times more in the following: eye problems, otitis media, tonsill hypertrophy, allergic diseases, etc. For female students in the 3rd year, prevalence rate showed little difference in 14 items(p<0.05). For items including eye problem, otitis media, tonsill hypertrophy, allergic disease, etc. it was shown that the rate was two times more between students with and without diseases. Physical examinations under the current school system are not producing any fundamental results for the health of the students. Methods and results are not trustworthy. Accordingly, a drastic overhaul of the current practices is needed in frequency, methods and items on the list in order to promote the health of the students. Cost-benefit studies as well as political considerations to ensure the development of efficient methods for physical examination are urgently needed at this moment.

  • PDF

Development on Early Warning System about Technology Leakage of Small and Medium Enterprises (중소기업 기술 유출에 대한 조기경보시스템 개발에 대한 연구)

  • Seo, Bong-Goon;Park, Do-Hyung
    • Journal of Intelligence and Information Systems
    • /
    • v.23 no.1
    • /
    • pp.143-159
    • /
    • 2017
  • Due to the rapid development of IT in recent years, not only personal information but also the key technologies and information leakage that companies have are becoming important issues. For the enterprise, the core technology that the company possesses is a very important part for the survival of the enterprise and for the continuous competitive advantage. Recently, there have been many cases of technical infringement. Technology leaks not only cause tremendous financial losses such as falling stock prices for companies, but they also have a negative impact on corporate reputation and delays in corporate development. In the case of SMEs, where core technology is an important part of the enterprise, compared to large corporations, the preparation for technological leakage can be seen as an indispensable factor in the existence of the enterprise. As the necessity and importance of Information Security Management (ISM) is emerging, it is necessary to check and prepare for the threat of technology infringement early in the enterprise. Nevertheless, previous studies have shown that the majority of policy alternatives are represented by about 90%. As a research method, literature analysis accounted for 76% and empirical and statistical analysis accounted for a relatively low rate of 16%. For this reason, it is necessary to study the management model and prediction model to prevent leakage of technology to meet the characteristics of SMEs. In this study, before analyzing the empirical analysis, we divided the technical characteristics from the technology value perspective and the organizational factor from the technology control point based on many previous researches related to the factors affecting the technology leakage. A total of 12 related variables were selected for the two factors, and the analysis was performed with these variables. In this study, we use three - year data of "Small and Medium Enterprise Technical Statistics Survey" conducted by the Small and Medium Business Administration. Analysis data includes 30 industries based on KSIC-based 2-digit classification, and the number of companies affected by technology leakage is 415 over 3 years. Through this data, we conducted a randomized sampling in the same industry based on the KSIC in the same year, and compared with the companies (n = 415) and the unaffected firms (n = 415) 1:1 Corresponding samples were prepared and analyzed. In this research, we will conduct an empirical analysis to search for factors influencing technology leakage, and propose an early warning system through data mining. Specifically, in this study, based on the questionnaire survey of SMEs conducted by the Small and Medium Business Administration (SME), we classified the factors that affect the technology leakage of SMEs into two factors(Technology Characteristics, Organization Characteristics). And we propose a model that informs the possibility of technical infringement by using Support Vector Machine(SVM) which is one of the various techniques of data mining based on the proven factors through statistical analysis. Unlike previous studies, this study focused on the cases of various industries in many years, and it can be pointed out that the artificial intelligence model was developed through this study. In addition, since the factors are derived empirically according to the actual leakage of SME technology leakage, it will be possible to suggest to policy makers which companies should be managed from the viewpoint of technology protection. Finally, it is expected that the early warning model on the possibility of technology leakage proposed in this study will provide an opportunity to prevent technology Leakage from the viewpoint of enterprise and government in advance.

A Study on the Change of AIDS Knowledge and Sexual Behavior among Middle and High School Students through AIDS Prevention Education (중고등학생의 에이즈 예방교육(豫防敎育)을 통한 에이즈 지식(知識)과 성의식(性意識) 변화(變化)에 관(關)한 연구(硏究))

  • Kwon, Kwan-Woo;Lee, Kyoung-Mu;Kim, Joung-Soon
    • Journal of the Korean Society of School Health
    • /
    • v.12 no.1
    • /
    • pp.109-129
    • /
    • 1999
  • AIDS is worldwide problem. It has threatens societies and is potentially a big problem among youth. UNAIDS has warned that collective global responses are necessary; with half of the newly infected being children and young people in 1998, educating youth below age 24 is essential. Because of both their unexpected, strong sexual activities and an easjer tendency to change their behavior than adults, UNAIDS emphasizes the importance of prevention education for youth. In Korea, 4 cases of HIV infection have officially been reported among high school students. Considering the potential seriousness of HIV infection among youth, the Korean AntiAIDS Federation (KAAF) began an education programme for Korean youth (middle & high school pupils) as one intervention method in 1993. The purpose of this study is to evaluate the impact of the education programs performed and to develop a better programme. The intervention method used in this study was mainly a lecture in a big or small auditorium or through broadcasting systems using audio-visual teaching aids. The period of this survey was from Nov. 10 to Dec. 26. in 1998. The subjects surveyed were 792 pupils who were sampled from 12 different middle and high schools in Seoul by a two-stage cluster sampling. Self-recording the structured questionnaire was used for data collection. Data were analyzed by using a paired t-test to compare the knowledge difference before and after the interrention method. A chi-square test to compare the consciousness difference between pre-post-education results was used, and an ANOVA was ased to compare the knowledge difference among the selected groups. Major results of this study are summarized as follows: (1) AIDS knowledge significantly changed after AIDS prevention education. (2) The direct lecture in a big or small auditorium is more effective than an indirect lecture through a broadcasting system or through audio-visual teaching aids. (3) Those who had not seen obscene materials (e.g. pornography films, magazines etc.) acguired much more knowledge than others after AIDS prevention education. (4) Those who had no girlfriend/or boyfriend acquired much more knowledge than the others after AIDS prevention education. (5) As to the attitudes toward chastity, more girls than boys and students who had not seen obscene materials rather than those who already had were liable to support the state ment: "all should remain chase" and their consciousness on "being chaste" changed much more than that of others after intervention. (6) As to the individual evaluation of lectures, 23.1% shows "very good", 44.1% "good", 26.9% "normar" '-' thus, the positive evaluation was to 94.2%. The negative response was 5.8%. (7) As to the desire for AIDS education sponsored by KAAF in the future, more than 90.5% showed a positive reaction. (8) As to the educators in future education methods, pupils wanted lecturers from outside their schood. (9) Students from vocational high schools have seen obscene materials much more than other groups and the percentage of those who had a girlfriend/or boyfriend was higher than that of the others as wello. (10) 90% of those who watched obscene materials responded that they experienced these materials while at middle school and 100% before reaching the second grade of high school. (11) The number of boys who have experienced obscene materials is twice as many as that of girls. (12) The percentage of boys who have a girlfriend is much higher than the percentage of girls who have a boyfriend. (13) Among those who have friends of the opposite sex, 11.1% say that they hare had sexual contact and 20.8% hare experienced kissing and caressing.

  • PDF

Community Ecological Study on the Quercus acuta Forests in Bogildo-Island (보길도(甫吉島) 붉가시나무림(林)의 군락생태학적(群落生態學的) 연구(硏究))

  • Kim, Chong-Young;Lee, Jeong-Seok;Oh, Kwang-In;Jang, Seok-Ki;Park, Jin-Hong
    • Journal of Korean Society of Forest Science
    • /
    • v.89 no.5
    • /
    • pp.618-629
    • /
    • 2000
  • This study was carried out to investigate ecological niche of Quercus acuta communities in Bogildo-island from July to October, 1998. This island is occupied by a subtropical evergreen broad-leaved forests. The study on community ecology of Q. acuta, mostly dominant species of subtropical forests, is very important for successful forest management. Sampling areas were selected in 16 quadrats, dominated by Q. acuta to examine the vegetation characteristics(plant identification, D.B.H.) and environmental elements (microtopography, altitude, slope degree, aspect, illumination and soil physicochemical properties). On the basis of data from field surveys, importance values were calculated for the dominance of Q. acuta and volume growth was analyzed by tree ring widths. The results obtained were as follows ; 1. The lists of vascular plants in the investigations were identified as 54 families, 91 genera, 113 species, 9 varieties, 1 formae. It appeared that 45 kinds were evergreen, 6 kinds(Camellia japonica, Ligustrum japonicum, Eurya japonica, Smilax china, Trachelospermum asiaticum var. intermedium, Carex lanceolata) were commonly observed in all plots and 5 species(Cinnamomum japonicum, Ardisia japonica, Cymbidium goeringii, Dryopteris bissetiana, Viburnum erosum) were most highly observed in all plots(over 80%). 2. The dominating species per strata were, Quercus acuta, Castanopsis cuspidata sp. Quercus salicina, Pinus thunbergii, Prunus sargentii in tree layer, Camellia Japonica, Ligustrum japonicum, Quercus acuta, Eurya japonica, Castanopsis cuspidata sp. in subtree layer, Camellia japonica, Ligustrum japonicum, Smilax china, Cinnamomum japonicum, Viburnum erosum in shrub layer and Trachelospermum asiaticum var. intermedium, Ardisia japonica, Carex lanceolata, Camellia japonica(seedlings), Quercus acuta(seedlings) in herb layer, all in descending orders. 3. Quercus acuta could be suggested as shade intolerant tree, considering the distribution in southern, western, nothern and eastern slopes in the descending orders. 4. Mean relative illumination in the forest is 0.89 % and it is relatively low in brightness. 5. Sustainment of Quercus acuta community couldn't be confirmed by judging from their reverse J curve in even-aged forest, as shown in D.B.H. distribution analysis. 6. The result of annual ring width analysis(mean ; 2.44 mm) showed three stages, such as a gentle increasing(1~12 year ; 2.04 mm), a relatively steep increasing(13~22 year ; 2.95 mm) and decreasing or stagnating(23 year after ; 2.41 mm).

  • PDF