• The Journal of the Korea Contents Association
• /
• v.11 no.12
• /
• pp.774-784
• /
• 2011

The purpose of this study, which was conducted as a part of investigations for vitalizing the School Sheriff system proposed as a means to prevent school violence and promote school safety, was to survey recognition of elementary school parents toward the School Sheriff system and present an improvement scheme for the system. For the study, we selected as the research object a set of parents whose children attended schools with School Sheriffs and then sampled 200 parents out of them with cluster random sampling, before analyzing 189 finally. Validity of the questionnaire is verified by expert council and factorial analysis, and reliability by reliability analysis. Statistical means including chi-square test, t-test and F-test are used. The result of the study as follows : First, necessity of the School Sheriff system varies by individual characteristics. Second, recognition toward the system itself varies by individual characteristics. Third, recognition toward the role that should be played by School Sheriffs varies by individual characteristics. Fourth, there is a difference in perceiving the role and activity of School Sheriffs, Fifth, whether the system helped improving school safety varies by individual characteristics. Sixth, the satisfaction from the School Sheriffs.

• Asian Journal of Turfgrass Science
• /
• v.15 no.3
• /
• pp.111-118
• /
• 2001

We observed air temperature and relative humidity in the green space why this research graspes effect of climate relax by coverage condition and height difference tree in green space of the 4ha scale. With this data, analyzed relationship of coverage and air temperature or relative humidity distribution, number of tree and climate relax by revolution analysis. In this result, higher zone formed barren area, lower zone did forest and surround grassland. Relative humidity have corresponding type of air temperature distribution. higher air temperature zone was lower humidity and lower zone was higher humidity. Coverage condition effect climate relax by increasing forest and grassland. and increasing number of tree effect climate relax no related hight of tree. This efficiency order of an arbor, subarbor.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.4
• /
• pp.199-208
• /
• 1993

Using several soil parameters which are obtained from the PI-experimental formulas and the back analysis method, the elastic analysis, the elasto-plastic analysis and the elasto-viscoplastic analysis for soil deformation are executed. Comparing the results with those of consolidation test, the indirect estimation method for soil parameters and the suitability of constitutive models are studied. The elastic analysis using back analysis result and the elasto-plastic analysis using the perconsolidation test. The elasto-viscoplastic analysis disagrees with the results of meability coefficient obtained from back analysis are the nearest to the results of the consolidation test. It is inferred that elasto-viscoplastic model is not adequate to the soil of which plasticity index is low.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.37 no.1
• /
• pp.37-43
• /
• 2017

Ultrasonic transducers with high resolution and resonant frequency are required to detect small defects (less than hundreds of ${\mu}m$) by ultrasonic testing. The resonance frequency and resolution of an ultrasonic transducer are closely related to the thickness of piezo-electric materials, backing materials, and the electric impedance matching technique. Among these factors, electrical impedance matching plays an important role because it can reduce the loss and reflection of ultrasonic energy differences in electrical impedance between an ultrasonic transducer and an ultrasonic defects detecting system. An LC matching circuit is the most frequently used electric matching method. It is necessary for the electrical impedance of an ultrasonic transducer to correspond to approximately $50{\Omega}$ to compensate the difference in electrical impedance between both connections. In this study, a 15 MHz immersion ultrasonic transducer was fabricated and an LC electrical impedance circuit was applied to that for having broad-band frequency characteristic.

• Proceedings of the ESK Conference
• /
• 1993.10a
• /
• pp.33-37
• /
• 1993

근래 우리나라에서도 평균수명이 길어져 노동의욕이 있는 중고령자가 증가하는 한편, 출산율이저 하되어 젊은 근로자의 수가 감소되고 있다. 통계청의 인구통계과의 추계에 의하면 2000년에는 60세 이 상이 총인구에 점하는 비율이 10.7%, 65세 이상은 6.8%가 되고, 2020년에는 60세 이상이 19.5%, 65세 이 상도 12.5%에 도달한다는 것이다. 인구노령화로 인한 고령화 사회에 대한 준비를 서둘러야 할 때라고 생각된다. 또 고령화 사회로 되면 젊은 연령층의 경제적 부담이 증가되므로 중고령자의 노동인구를 이대 로 방치해 두는 것은 국가적으로나 사회복지적으로나 불경제라고 할 수 있다. 그런데, 문제가 되는 것은, 중고령자를 취업시키는 것이 오히려 사회의 생산성을 저하시키거나 경제적으로 불리하게 되어서는 안되는 것과 중고령노동자 자신의 안전을 확보해야 하는 것이다. 이러한 문제를 해결하기 위해서는 고용에 있어 서 어떠한 점에서 중고령노동자에게 특징과 문제가 있는가를 분명히 할 필요가 있다. 고령자는 청년자 보다 노동능력이 떨어지는 특징과 문제가 있는가를 분명히 할 필요가 있다. 고령자는 청년자 보다 노동능력이 떨어지는 경향이 있지만 개인차도 크고 고령자 중에는 청년자의 기능에 비교해도 뒤떨어지지 않는 자도 있다. 연령만으로 노동능력을 판정하는 것은 적절한 방법이라고 할 수 없다. 문헌에 의하면 역연령(chornological age)이 25세의 경우, 생리적 연령은 23세에서 27세로 4년 차이가 있다고 한다. 이러한 생리적 연령의 차이는 역연령이 더해감에 따라서 점차 크게 되어 역연령이 45세에서는 12년, 80세 에서는 20년이나 된다는 것이다. 이것은 인간에 있어서 시간적 경과를 나타내는 역연령 이외에 신체적 기능연령(functional age)가 있다는 것을 의미하는 것이다. 한편, 생산현장에서는 자동화, 기계화가 진보되어 육체적인 노동이 경감된 결과, 중고령자라도 할 수 있는 작업이 많아지고 있다. 또, VDT (Visual Dislay Terminal) 작업과 같은 정보처리 작업의 수요가 증가하여 그 인재의 부족이 지적되고 있다. 따라서 중고령자의 기능을 조사하여 어떠한 작업에 적합한가를 판단하는 것이 중요한 과제로 되었다. 그러나 노동에는 많은 기능이 관여 하고, 그 내용에 따라서 요구되는 기능이 서로 다르기 때문에 노동적응능력의 기본적인 기능으로 보여지는 것에 좁혀서 작업능력의 연령증가 변화에 대하여다원적 평가를 하는 것이 실제적이라고 할 수 있다. 따라서 본 연구에서는 인간이 가지고 있는 다수의 기능중에서 수지교 치성과 연령증가와의 관계를 조사한다. 만약 연령증가 만으로 수지교치성을 평가 할 수 없는 경우에는 어떠한 요인이 수지기민성의 변화에 영향을 미치는가를 검토한다.

• Korea Trade Review
• /
• v.43 no.3
• /
• pp.219-243
• /
• 2018

This study focused on the rapidly growing Chinese market by developing an evaluation model for overseas direct sales websites for Chinese consumers. In addition, we developed specific strategic alternatives for each sub-market by conducting multi-group analysis for each consumer's characteristics. Results showed that the level of concern about site use had a stronger impact on persistent use behavior. In addition, among antecedents that affect the level of assurance and concern, we found that these includes not only the perceived benefits and perceived risk factors identified in previous studies but also social-cultural factors. In addition, this study compares the evaluation of overseas direct sales website according to the level of involvement of users. This study analyzes the differences in coefficients among the paths and suggest practical implications for each group.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.5 no.2
• /
• pp.169-176
• /
• 2000

This study was carried out to clarify the spatial and temporal patterns of macrobenthic assemblages on the subtidal area around Mokpo, southwest of Korea. A total of 238 species and 663 ind./$m^{2}$ were collected. Polychaetes were the most abundant faunal group that comprised 88 species and had a mean density of 389 ind./$m^{2}$. In the semi-enclosed Youngsan River estuarine bay and neighbouring Mokpo Port area were composed of fine sediments with high organic content, and revealed large seasonal variations in the salinity of surface water and bottom dissolved oxygen in contrast to little seasonal changes in those parameters in the outer area. The study area was classified into four station groups by the cluster analysis; the harbor area, the offshore area, and the inner and outer estuarine bay. Two estuarine bay areas showed different species composition; the dominant species of inner bay were Tharyx sp., Poecilochaetus johnsoni, Heteromastus filiformis and other opportunistic species whereas those in the outer bay were Ruditapes philippinarum, Corophium sinense. From the environmental data and species composition of benthic community, the inner bay was characterized to have unstable benthic faunal assemblages, especially under the seasonal disturbance and receiving large amount of organic matter input and intermittant discharge of fresh water. The coastal developments around Mokpo city also seem to have stressed the subtidal communities spatio-temporally.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.734-743
• /
• 2007

The KTX station is one of special generators that produce a lot of trips caused by special land use such as university, airport, and super shopping mall. Special generators need special attention in developing travel demand models since the standard trip generation and distribution model in the conventional four-step approach do not provide reliable estimates of their travel patterns. New modeling approach, activity-based model, considering travel behavior of person, seem to be more appropriate for those special generators. Thus, this study introduces a spatial-temporal activity-based approach and how activity-based approach can be applied to estimation of travel demand at KTX stations.

• Journal of the Korean Geotechnical Society
• /
• v.25 no.9
• /
• pp.93-100
• /
• 2009

A core procedure of the direct search method used in this study is optimizing a difference between objective function and real displacement and correcting unknown variables. Because the research procedure comes from back-analyzing of the unknown variable of each layer, back-analyzing results need an additional optimization to minimize interferential effects of unknown variables. Therefore, the direct search method Is used to obtain optimized solutions without a partial differentiation of an objective function. The object of this research is developing the back analysis technique for multi-unknown variables by modeling the soil including underground structure Into upper and lower layer. In order to minimize interferent errors, repeated back analysis is performed and applicability on the real tunnel is examined. Consequently, the multi-layer analysis model is more precise in describing the real behavior of underground structure. It shows the validity of back analysis far multi-layer model which is the understructure placed on multi-layer boundaries.

• Journal of dental hygiene science
• /
• v.10 no.5
• /
• pp.329-334
• /
• 2010

This study was performed to identify the relationship between scaling behaviors and knowledge about scaling and oral health belief of worker, and to provide baseline data for developing industry oral health policy. The survey had conducted self-administered questionnaires by 326 workers in Gyeongsan and Yeongcheon areas in Gyeongbuk province. Their scaling behaviors, knowledge and oral health belief were measured. The results were as follow; The average score of knowledge about scaling was 6.44. The average oral health belief was 2.72. In detail, 'usefulness' was 3.24 as the highest and 'seriousness' was 2.25 as the lowest. The periodic scaling and scaling cycle were associated with 'seriousness' and 'barrier' as positive correlation(p<.05, .01). On the other hand, they were associated with knowledge and 'usefulness' as negative correlation(p<.01). Meanwhile, scaling motive showed positive correlation with 'cue of action'(p<.01), showed negative correlation with knowledge(p<.01). In the correlation between knowledge about scaling and oral health belief, knowledge showed negative correlation with 'barrier'(p<.01) and showed positive correlation with 'usefulness'(p<.01). Finally, we need to advertise and manage the importance of scaling politically and makes people do the voluntary scaling in six-month intervals in order to keep the periodontal health of worker.