• Title/Summary/Keyword: Level set methods

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Quantum Mechanical Investigation for the Structure and Vibrational Frequencies of Dimethyldioxirane (Dimethyldioxirane의 분자구조와 Vibrational Frequencies에 대한 양자역학적 고찰)

  • Kang, Chang Duk;Kim, Seung Joon
    • Journal of the Korean Chemical Society
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    • v.42 no.1
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    • pp.9-15
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    • 1998
  • The geometrical parameters, vibrational frequencies, and IR intensities of dimethyldioxirane had been investigated using high level ab initio quantum mechanical methods with various basis sets. The polarization function decreases C-O and C-C bond distances significantly and the electron correlation effect increases those bond lengths slightly, while other bond lengths and bond angles are relatively stable for basis set size and correlation effect. The experimental and other theoretical vibrational frequencies and IR intensities of dimethyldioxirane will be compared and discussed with our high level theoretical predictions.

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Effect of the Confusion Level of Dual-Tasks Using a Smartphone on the Gait of Subjects with Chronic Ankle Instability While Walking (보행 중 스마트폰을 이용한 이중과제의 혼란수준이 만성 발목불안정성 성인의 보행에 미치는 영향)

  • Choi, Woo-Sung;Choi, Jong-Duk
    • Journal of the Korean Society of Physical Medicine
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    • v.15 no.3
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    • pp.99-108
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    • 2020
  • PURPOSE: This study examined the effects of the confusion level in performing dual tasks using smartphones while walking in subjects with chronic ankle instability (CAI). METHODS: Twenty subjects with CAI and 20 healthy subjects participated in the study. The spatial, temporal, spatial-temporal, and variability gait parameters were measured using GAITRite under four different conditions: general gait, web surfing during gait, texting during gait, and gaming during gait. Two-way repeated-measures analysis of variance was used to analyze the interaction according to the group (2) and confusion level in dual-tasks (4). One-way repeated-measures analysis of variance was used to compare the changes within the group according to the confusion level in dual-tasks. The changes between groups were compared using an independent t-test. The statistical significance level was set to p = .05. RESULTS: Significant interactions in the temporal and spatial-temporal gait parameters were found between the dual-task conditions and the other groups (p < .05). Significant within-group differences in the spatial, temporal, and spatial-temporal gait parameters were found according to the confusion level in dual tasks (p < .05). Significant between-group differences were observed in the temporal and spatial-temporal gait parameters according to the confusion level in dual tasks (p < .05). CONCLUSION: The effect of the confusion level in dual tasks was greater in subjects with CAI than in healthy individuals. This study suggests that to prevent reinjury to the ankle, subjects with CAI should avoid dual tasks such as using smartphones while walking.

A Study on the Relationship between Class Similarity and the Performance of Hierarchical Classification Method in a Text Document Classification Problem (텍스트 문서 분류에서 범주간 유사도와 계층적 분류 방법의 성과 관계 연구)

  • Jang, Soojung;Min, Daiki
    • The Journal of Society for e-Business Studies
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    • v.25 no.3
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    • pp.77-93
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    • 2020
  • The literature has reported that hierarchical classification methods generally outperform the flat classification methods for a multi-class document classification problem. Unlike the literature that has constructed a class hierarchy, this paper evaluates the performance of hierarchical and flat classification methods under a situation where the class hierarchy is predefined. We conducted numerical evaluations for two data sets; research papers on climate change adaptation technologies in water sector and 20NewsGroup open data set. The evaluation results show that the hierarchical classification method outperforms the flat classification methods under a certain condition, which differs from the literature. The performance of hierarchical classification method over flat classification method depends on class similarities at levels in the class structure. More importantly, the hierarchical classification method works better when the upper level similarity is less that the lower level similarity.

Context Prediction Using Right and Wrong Patterns to Improve Sequential Matching Performance for More Accurate Dynamic Context-Aware Recommendation (보다 정확한 동적 상황인식 추천을 위해 정확 및 오류 패턴을 활용하여 순차적 매칭 성능이 개선된 상황 예측 방법)

  • Kwon, Oh-Byung
    • Asia pacific journal of information systems
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    • v.19 no.3
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    • pp.51-67
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    • 2009
  • Developing an agile recommender system for nomadic users has been regarded as a promising application in mobile and ubiquitous settings. To increase the quality of personalized recommendation in terms of accuracy and elapsed time, estimating future context of the user in a correct way is highly crucial. Traditionally, time series analysis and Makovian process have been adopted for such forecasting. However, these methods are not adequate in predicting context data, only because most of context data are represented as nominal scale. To resolve these limitations, the alignment-prediction algorithm has been suggested for context prediction, especially for future context from the low-level context. Recently, an ontological approach has been proposed for guided context prediction without context history. However, due to variety of context information, acquiring sufficient context prediction knowledge a priori is not easy in most of service domains. Hence, the purpose of this paper is to propose a novel context prediction methodology, which does not require a priori knowledge, and to increase accuracy and decrease elapsed time for service response. To do so, we have newly developed pattern-based context prediction approach. First of ail, a set of individual rules is derived from each context attribute using context history. Then a pattern consisted of results from reasoning individual rules, is developed for pattern learning. If at least one context property matches, say R, then regard the pattern as right. If the pattern is new, add right pattern, set the value of mismatched properties = 0, freq = 1 and w(R, 1). Otherwise, increase the frequency of the matched right pattern by 1 and then set w(R,freq). After finishing training, if the frequency is greater than a threshold value, then save the right pattern in knowledge base. On the other hand, if at least one context property matches, say W, then regard the pattern as wrong. If the pattern is new, modify the result into wrong answer, add right pattern, and set frequency to 1 and w(W, 1). Or, increase the matched wrong pattern's frequency by 1 and then set w(W, freq). After finishing training, if the frequency value is greater than a threshold level, then save the wrong pattern on the knowledge basis. Then, context prediction is performed with combinatorial rules as follows: first, identify current context. Second, find matched patterns from right patterns. If there is no pattern matched, then find a matching pattern from wrong patterns. If a matching pattern is not found, then choose one context property whose predictability is higher than that of any other properties. To show the feasibility of the methodology proposed in this paper, we collected actual context history from the travelers who had visited the largest amusement park in Korea. As a result, 400 context records were collected in 2009. Then we randomly selected 70% of the records as training data. The rest were selected as testing data. To examine the performance of the methodology, prediction accuracy and elapsed time were chosen as measures. We compared the performance with case-based reasoning and voting methods. Through a simulation test, we conclude that our methodology is clearly better than CBR and voting methods in terms of accuracy and elapsed time. This shows that the methodology is relatively valid and scalable. As a second round of the experiment, we compared a full model to a partial model. A full model indicates that right and wrong patterns are used for reasoning the future context. On the other hand, a partial model means that the reasoning is performed only with right patterns, which is generally adopted in the legacy alignment-prediction method. It turned out that a full model is better than a partial model in terms of the accuracy while partial model is better when considering elapsed time. As a last experiment, we took into our consideration potential privacy problems that might arise among the users. To mediate such concern, we excluded such context properties as date of tour and user profiles such as gender and age. The outcome shows that preserving privacy is endurable. Contributions of this paper are as follows: First, academically, we have improved sequential matching methods to predict accuracy and service time by considering individual rules of each context property and learning from wrong patterns. Second, the proposed method is found to be quite effective for privacy preserving applications, which are frequently required by B2C context-aware services; the privacy preserving system applying the proposed method successfully can also decrease elapsed time. Hence, the method is very practical in establishing privacy preserving context-aware services. Our future research issues taking into account some limitations in this paper can be summarized as follows. First, user acceptance or usability will be tested with actual users in order to prove the value of the prototype system. Second, we will apply the proposed method to more general application domains as this paper focused on tourism in amusement park.

A Study on the Post-Purchase Behavior of Durable Goods in Korea Rural Household (한국 농촌 가정의 내구재 구매후 행동에 관한 연구)

  • 박옥임
    • Journal of Families and Better Life
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    • v.1 no.2
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    • pp.75-88
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    • 1983
  • This study intends to examine the relations between the demographical and the socioeconomic variables on the post-purchase behavior of durable goods in rural household . Several concrete hypothesis in the above study were set as follows: 1) The evaluation on the post-purchase of rural household might be differently made in accordance with sex, age, resident district, education level, income level, family type and user's own purchasing, etc. 2)There can be differences in the attitude on the post-purchase of rural household in accordance with sex, age, resident district, education level, income level, family type and user's own purchasing, etc. 3) It must be of necessity to habe correlation between the evaluation and the attitude of the post- purchase. To examine these hypothesis, the study used the 27 questionnaires which are composed of 7 subject for general characteristics and 10 subjects respectively for the post-purchase evaluation and attitude of 285 rural households in Chon Nam Province. They were interviewed for 11days from Apr. 1st, 1983 to Apr. 11 the, 1983. Statistical methods such as frequency, percentage, Chi-Square test, arithmetical mean, t-test, F-test and Pearson's correlation coefficients, etc. are used for the data analysis. The summary and the conclusion resulted form such analysis are as follows; First, high significances are shown on the age the resident district the education level and the family type as significant variables affecting on the post-purchase evaluation of the rural house hold. Second, high significances are shown on the education level, the income level, the family type and the users own purchasing, etc. as significant variables affecting on the post-purchase attitude of rural household. Third, correlations between the post-purchase evaluation and the post-purchase attitude are very close. Therefore the hypothesis 1)and 2) of this study were accepted partially and the hypothesis 3) was confirmed wholely.

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Multilevel Analysis of Factors Associated with Perceived Good Health and Multimorbidity among Older Adults: Using the 2017 Community Health Survey

  • Boo, Sunjoo;Han, Young Ran;Choi, Hye Young
    • Research in Community and Public Health Nursing
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    • v.31 no.spc
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    • pp.549-562
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    • 2020
  • Purpose: This study aimed to identify individual- and regional-level factors associated with perceived good health and multimorbidity among older adults. Methods: Secondary analysis of the 2017 Korea Community Health Survey was conducted on a sample of 67,532 older adults. The individual level data set was combined with regional-level factors from the administrative data released on the Korea National Statistical Office website. Distribution of perceived good health and multimorbidity in 254 public health centers were calculated using sampling weights and presented as percentages. Multilevel logistic regression analyses were used to identify individual- and regional-level factors associated with perceived good health and multimorbidity. Results: Overall, 21.1% of subjects perceived their health to be good, ranging from 9.3% to 39.4% by region. The prevalence of multimorbidity was 15.9%, and varied between 6.6% and 22.6% by region. At the individual level, perceived good health was associated with men, younger age, higher educational levels, higher income levels, and those married and living with a partner and maintaining a healthy lifestyle. At the regional level, higher rates of health center personnel among public officials and higher levels of financial independence were associated with perceived good health. Multimorbidity was associated with marital status and healthy lifestyle, and higher rates of health center personnel among public officials. Conclusion: Regional factors such as health care personnel and local economy could affect population health. Our findings suggest the need to consider individual- and regional-level factors to promote good health among older adults and reduce the health gap by region.

Relationship Between Titleist Performance Institute Level 1 Test and the Performance of Professional Golf Players (프로 골프선수의 TPI Level 1 Test Score에 따른 경기력 수준 분석)

  • Kim, Jae-Eun;Do, Kwang-Sun;Kim, Cheong
    • Journal of The Korean Society of Integrative Medicine
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    • v.10 no.2
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    • pp.27-35
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    • 2022
  • Purpose : The purpose of this study is to analyze the correlation between the TPI Level 1 test and the performance of KPGA professional golf players. Methods : In 2019, 30 KPGA golf players attempted in the TPI Level 1 test. Their performance was then compared with the test based on the players' aggregated official records on the KPGA website, The most meaningful prize money ranking, average driving distance, fairway landing rate, and average number of putts were considered to evaluate their performance. Additionally, to obtain the average value of the players' accumulated records, the period from the first game in March 2019 to the end of October was considered. Results : The criterion for the difference between the upper group and the lower group was set based on the 9 points of the TPI Level 1 test, which showed the most significant difference. The prize money ranking stood at 63.00±51.77 in the upper group and 113.92±68.79 in the lower group in the TPI Level 1 test, the difference was significantly higher (p<.05) for the upper group (p<.05). The average driving distance was 286.15±10.06 yds for the upper group and 277.39±8.49 yds for the lower group, group, with the driving distance significantly higher in the upper group (p<.05). Further, the average number of putts for the upper group was 1.81±.02 and 1.85±.04 for the lower group, indicating a significant difference. Conclusion : A higher TPI Level 1 test score is likely to have a positive effect on performance.. As a result of the statistical values of this study, it was found that players must possess at least 9 out of 17 types of physical abilities Therefore, it can be considered that training and intervention to acquire these physical abilities are essential.

Evaluation of 2+1 Roads Application to Improve Rural Two-lane Highway in Korea (국내 2+1차로 도로 도입에 따른 교통운영 및 경제적 비용 측면의 기대효과 분석)

  • Chae, Chan Dle;Lee, Dong Min;Cho, Han Seon
    • International Journal of Highway Engineering
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    • v.15 no.3
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    • pp.85-92
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    • 2013
  • PURPOSES: The purpose of this paper is to estimate expected effects on traffic operational and economic aspects of 2+1 roads application in Korea. METHODS : Micro simulation study using VISSIM 5.0 was used to analyze the operation efficiency of 2+1 roads compared to two-lane highways and four-lane highways. Some scenarios for various traffic volumes were set up in order to analyze the effect of 2+1 roads under various traffic situations. Also imaginary road networks were set up for each type of roads. The MOEs to measure the operation efficiency were selected with average travel speed and delay. For analyzing economic effect of 2+1 roads, construction cost of a specific imaginary 2+1 road was compared to construction cost of a four-lane highway with same conditions. RESULTS: The results of study show that a 2+1 road is more effective with 19 percents higher average travel speed and 39 percents lower average delay than a two-lane highway. In the economic analysis, construction costs to construct a 2+1 road are saved as approximately 26.4~40.7 percents when compared to construction of four-lane highway. CONCLUSIONS: It can be concluded that 2+1 roads can improve the traffic operational level of service for two-lane highways and 2+1 roads can be applied as an effective design alternative for higher-volume two-lane highways in Korea.

Statistical Analysis for Feature Subset Selection Procedures.

  • Kim, In-Young;Lee, Sun-Ho;Kim, Sang-Cheol;Rha, Sun-Young;Chung, Hyun-Cheol;Kim, Byung-Soo
    • Proceedings of the Korean Society for Bioinformatics Conference
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    • 2003.10a
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    • pp.101-106
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    • 2003
  • In this paper, we propose using Hotelling's T2 statistic for the detection of a set of a set of differentially expressed (DE) genes in colorectal cancer based on its gene expression level in tumor tissues compared with those in normal tissues and to evaluate its predictivity which let us rank genes for the development of biomarkers for population screening of colorectal cancer. We compared the prediction rate based on the DE genes selected by Hotelling's T2 statistic and univariate t statistic using various prediction methods, a regulized discrimination analysis and a support vector machine. The result shows that the prediction rate based on T2 is better than that of univatiate t. This implies that it may not be sufficient to look at each gene in a separate universe and that evaluating combinations of genes reveals interesting information that will not be discovered otherwise.

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Assessing the Functional Status of Acute Stroke Patients using ICF Core Set-short Form (단축형 ICF 핵심지표로 측정한 뇌졸중 환자의 기능상태)

  • Kang, Jiyeon;Gong, Ju;Park, Mi-Jin;Lee, Yeo-Won;Kim, Yuri
    • Journal of muscle and joint health
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    • v.20 no.1
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    • pp.22-30
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    • 2013
  • Purpose: The International Classification of Functioning, Disability and Health (ICF) model was proposed by the World Health Organization for enhancing interdisciplinary communication. The purpose of this study was to examine the functional status of acute stroke patients using ICF core sets-short form. Methods: A set of 15 ICF items on functional status was used by nurses for their daily nursing assessment on functional status in 44 acute stroke patients in a university hospital. Results: The highest level of function was "consciousness", while the lowest was "defecation". Compared with functional status on the first day, consciousness, ingestion, language (mental), and defecation functions were significantly improved on the 14th day. However, there was no significant changes in items on activity and participation or environmental functions. Conclusion: These findings suggest that the function-specific nursing interventions for acute stroke patients need to be developed. Future research needs to test the usefulness of ICF items as an measurement tool.