• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.427-434
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• 2005

An experimental investigation was carried out in order to verify the compressive strength, flexural strength, equivalent bending strength, rebound rate of shotcrete according to silicate accelerator, aluminate accelerator, cement mineral accelerator respectively and to especially evaluate the performance of shotcrete using cement mineral accelerator for high quality. The test result of compressive strength was showed that all accelerators were satisfied the required test value for each age, for the requirement of having the $75\%$ or higher compressive strength ratio to plain concretes at 28 days, cement mineral accelerator with $87\%$ compressive strength ratio was only satisfied. In flexural strength test, cement mineral accelerator was satisfied the flexural strength requirement in steel fiber reinforced shotcrete for each age. Aluminate type was conformed to the requirement for 28 days, but not at 1 day, silicate type was failed to satisfy standard requirement. Rebound rate was measured between $11{\~}19\%$ and cement mineral accelerator was showed comparatively lower rebound rate. Based on the test results, cement mineral accelerator exhibited excellent strength improvement and lower rebound rate compared to the conventional accelerator, its result is showed the possibility of making high performance shotcrete.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3163-3167
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• 2014

Background: Breast-conserving surgery (BCS) plus radiotherapy is equivalent to modified radical mastectomy (MRM) in terms of outcome. However there is wide variation in mastectomy rates dependent both on tumour and patient characteristics. Objective: This study aimed to assess the determinants of surgery choice in Asian patients with early breast cancer in a middle-income country. Materials and Methods: 184 patients with early breast cancer treated between Jan 2008 and Dec 2010 were recruited to complete a questionnaire. Chi-square test was used to analyze the association between surgery choice and demographic and tumour factors, surgeon recommendation, family member and partner opinions, fear of recurrence, avoidance of second surgery, fear of disfigurement, interference with sex life, fear of radiation and loss of femininity. Results: 85 (46%) had BCS while 99 (54%) had mastectomy. Age >60, Chinese ethnicity, lower education level, and larger tumour size were significantly associated with mastectomy. Surgeon recommendation was important in surgery choice. Although both groups did not place much importance on interference with sex life, 14.1% of the BCS group felt it was very important compared to 5.1% in the mastectomy group and this was statistically significant. There was no statistical difference between the two groups in terms of the other factors. When analyzed by ethnicity, significantly more Malay and Indian women considered partner and family member opinions very important and were more concerned about loss of femininity compared to Chinese women. There were no statistical differences between the three ethnic groups in terms of the other factors. Conclusions: When counseling on surgical options, the surgeon has to take into account the ethnicity, social background and education level, age and reliance on partner and family members. Decision-making is usually a collective effort rather than just between the patient and surgeon, and involving the whole family into the process early is important.

• Journal of Labour Economics
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• v.27 no.2
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• pp.91-115
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• 2004

Based on household characteristics, this study analyzes the sources of changes in income class. Using KLI panel data in 1998 and 2001, household equivalent income is calculated and households whose income class is changed are identified. Various household characteristics are examined to understand which characteristics are influential in income class changes. Empirical estimations are carried out by employing an ordered probit model. Region of residence, age of household head, education level of the head, the number of employed family members in 1998, and a change in the number of employed family members are shown to be statistically significant. Calculation of marginal probability based on the ordered probit estimation results show that the probability of upward movement in income class decreases as a household lives in rural areas, while the probability of upward movement increases as the household's head is better educated, the number of employed family members are higher and there is a higher increase in the number of employed family members. Age of the head has mixed results; while the probability of upward movement in income class decreases as the head gets older for the households in middle and high income classes, that probability increases as the head is in the range of the 40s and the 50s in low income class households.

• Journal of Labour Economics
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• v.38 no.4
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• pp.1-29
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• 2015

The Individual Retirement Pension (IRP) enables workers to continuously receive a retirement pension even when workers change their jobs in different companies and so it performs a bridge fund as the complimentary living expenses until they receive government public pension. Although the Korean government has forced workers to maintain an IRP account until their retirement age and to close their accounts only when they want to do so, it is not clear to measure its really effectiveness and, in fact, most of IRP accounts have been terminated immediately after the changes of their jobs. In this respect, IRP has not performed the bridge role for the future retirement pension income. We provide an economic decision-making model of both government and workers, where the retirement benefits related with the IRP are explicitly considered. Our model is required to select specific severance pay systems to maximize the income security and stability for their future old ages. It is concluded that the need of workers on the severance pay system is automatically revealed into the switch to IRP when workers are out from their current jobs, which is equivalent to the effect of gradually unifying the dual system of the retirement payment. In additoin, our empirical data indicates the relatively higher probability of termination on IRP for the older male workers having the more retirement deposit.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.245-253
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• 2004

The 36km-long Daebo-Campo coast has a well-developed marine terraces divided to six steps by elevation of paleoshoreline : 0.5 m(T1), 10 m(T2), 30 m(T3), 40 m(T4), 60 m(T5) and 75 m(T6). The 2$^{nd}$ and 3$^{nd}$ platforms in Daebo to Guryongpo are wider and more distinctive than those of Guryongpo to Gampo. The 3$^{nd}$ terrace of 30 m high is subdivided to two flights as lower(T3b) and upper(T3a) by old sea cliff. Platform age is unclear because of coral fossil free. However, the terrace age could be determined with convergent OSL ages from beach sediments on 2$^{nd}$ step(T2). OSL ages of the terrace of 10 m high range in 60-70 ka. It reveals that the 2$^{nd}$ -step platform correlates to Oxygen Isotope Time scale, substage 5a(ca. 80 ka), and that uplift rate is ca. 0.19 m/ka for 2$^{nd}$ terrace at Daebo-Campo coast. If considering equivalent uplift rate for all terraces since the Late Pleistocene, the 3$^{rd}$ and 4$^{th}$ terraces would be 5e substage and 7 stage. The 30 m-high terrace provides a good indicator for uplift at Daebo-Gampo coast since 125,000 yrs(MIS 5e). It suggests that the local neotectonic deformation might cause an optional uplift rate of ca. 0.19 m/ka along the SE coast of Korea.

• International Journal of Highway Engineering
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• v.18 no.1
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• pp.13-21
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• 2016

PURPOSES : In this study, we analyzed the compressive strength characteristics of lean base concrete in relation to changes in the outdoor temperature after analyzing the cold and hot weather temperature standards and calculated the minimum and maximum temperatures when pouring concrete. We examined the rate of strength development of lean base concrete in relation to the temperature change and derived an appropriate analysis formula for FRC base structures by assigning the accumulated strength data and existing maturity formula. METHODS : We measured the strength changes at three curing temperatures (5, 20, and $35^{\circ}C$) by curing the concrete in a temperature range that covered the lowest temperature of the cold period, $5^{\circ}C$, to the highest temperature of the hot period, $35^{\circ}C$. We assigned the general lean concrete and FRC as test variables. A strength test was planned to measure the strength after 3, 5, 7, 14, and 28 days. RESULTS : According to the results of compressive strength tests of plain concrete and FRC in relation to curing temperature, the plain concrete had a compressive strength greater than 5 MPa at all curing temperatures on day 5 and satisfied the lean concrete standard. In the case of FRC, because the initial strength was substantially reduced as a result of a 30% substitution of fly ash, it did not satisfy the strength standard of 5 MPa when it was cured at $5^{\circ}C$ on day 7. In addition, because the fly ash in the FRC caused a Pozzolanic reaction with the progress into late age, the amount of strength development increased. In the case of a curing temperature of $20^{\circ}C$, the FRC strength was about 66% on day 3 compared with the plain concrete, but it is increased to about 77% on day 28. In the case of a curing temperature of $35^{\circ}C$, the FRC strength development rate was about 63% on day 3 compared with the plain concrete, but it increased to about 88% on day 28. CONCLUSIONS : We derived a strength analysis formula using the maturity temperatures with all the strength data and presented the point in time when it reached the base concrete standard, which was 5 MPa for each air temperature. We believe that our findings could be utilized as a reference in the construction of base concrete for a site during a cold or hot weather period.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.58-64
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• 2012

Due to the influence of global oil prices, industrial productivity, which oil consumption is high, was significantly reduced. AC type of high-strength PHC piles is being manufactured through twice the steam curing process and this have resulted in a significant rise for product's manufacturing costs. NAC way other types of file manufacturing process has the advantage of reducing manufacturing costs by a turn of the steam curing. Nevertheless, because the initial strength be poor than that of AC method, shipment is being after the curing period of approximately three days. In addition, the growth of the product enhance with curing period can not be avoided, as a result, cost of inventory is acting as the rise. Piles by the AC method is immediately shipped after curing, damaging problems does not occur when they are introduced to the field site (for example, pile on-site). In the case of NAC, however, at least after the curing period of three days and after expressing the strength of 80 MPa or more, they are shipped on the scene. Therefore, NAC type has problems as follows: (1) increase in moderate inventory holding costs with type and (2) breakage in the field due to lack of strength. In this study, for NAC-typed PHC files, mixing characteristics research for the strength development at 1 day equivalent to AC method were conducted and strength characteristics with changes of original materials were evaluated were also identified.

• Journal of Distribution Science
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• v.12 no.8
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• pp.91-102
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• 2014

Purpose - Today, the importance of the service industry has increased. Social welfare businesses that follow the non-profit principle have neglected the distribution of the service. However, an intangible service, when produced and consumed, has a similar service delivery system to common service distribution and social welfare. Therefore, the author has assumed the efficiency of the service delivery system of social welfare to be equivalent to the service distribution industry. Hence, various kinds of social welfare services for the prevention of elderly suicide, from the perspective of distribution, are discussed. Studies on generational relations have thus far investigated depression from parent-children conflict, and satisfaction with their lives. Studies on the relationship between family solidarity and elderly suicide by analyzing existing social problems are rare. This study investigated the effects of family solidarity between old parents and adult children upon elderly suicide by analyzing serious psychological and social problems. This study revealed basic measures for elderly suicide prevention through services that could elevate family solidarity from the perspective of social welfare service distribution. Research design, data, and methodology - The subjects were 468 elderly, 65 years or older, at 18 senior welfare centers and halls for the elderly at Seoul and Gyeonggi-do. Questionnaire surveys, excluding invalid answers, were analyzed. Convenience sampling was used from February 5, 2014 to March 5, 2014. The findings were: First, women and those having spouses with advanced educational backgrounds and social activities had primary solidarity such as contact solidarity, affectionate solidarity, functional solidarity (giving help), and functional solidarity (receiving help). In addition, those who had good health, from a subjective point of view, had more solidarity. Second, the elderly who were men and single, and who had poorer educational backgrounds thought of suicide, lacked social activities, and had poor health, from a subjective point of view. Third, family solidarity between old parents and adult children had significantly negative influence on the suicidal ideation of the elderly. Results - The study revealed the following implications. First, the preparation for old age should consider not only economic welfare but also the psychological welfare due to the relationship with children. Second, the phenomenon of elderly suicide because of a lack of family solidarity could increase national loss and have great influence upon welfare in old age. Therefore, planning of welfare services for the elderly should consider the value of relationships with children to improve the psychological welfare of the elderly. Third, the social expenses of government-oriented support for parents should be discussed from the people's point of view. Conclusions - The subjects of the study comprised the elderly at Seoul and Gyenggi-do; therefore, it would be difficult to extrapolate the findings to all the elderly in the nation. The subject visited senior welfare centers as well as halls for the elderly; therefore, it would be difficult to assume that the trends were representative of the elderly in the nation.

• Journal of Conservation Science
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• v.34 no.6
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• pp.481-492
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• 2018

We conducted TL/OSL dating for the earthenware kilns in the Bongsan-ri archaeological site, Osong, which was occupied from the late nineteenth to the late twentieth century. With the SAR-TL/OSL method, paleodose was determined from the equivalent dose during the burial period($ED_{burial}$), the background dose($ED_{BG}$), the fading correction factor(f), and the overestimation correction factor(C). The annual dose rates and their provenance were evaluated from the measurement of natural radionuclides $^{238}U$, $^{232}Th$, and $^{40}K$. Because the comprehensive absolute age was provided by combining the resulting TL/OSL and radiocarbon data, we concluded that, for the absolute chronology of a modern archaeological site, TL/OSL dating and radiocarbon dating must be carried out together and summed. The construction and occupation of earthenware kilns in the Bongsan-ri site had changed from stage I (No.5, 6 kilns), to stage II (No.1, 2, 3 kilns), to stage III (No.4) in chronological order. When Bayesian statistics were applied, we found that the absolute ages of occupation for stages I, II, and III correspond to AD $1910{\pm}23$, AD $1970{\pm}10$, and AD $1987{\pm}4$. These results were in good agreement with the archaeological context or chronology.

• Therapeutic Science for Rehabilitation
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• v.11 no.3
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• pp.65-80
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• 2022

Objective : This study examined the psychometric properties of the 12-item Coping Orientation to Problems Experienced Scale (COPE) using Rasch analysis. COPE is one of the instruments used to measure stress-coping skills. Methods : The study participants were 480 community-dwelling older adults. We tested the instrument's unidimensionality assumption using principal component analysis (PCA). Item fit was examined using infit-and-outfit mean-square (MnSq) and standardized fit statistics (ZSTD). The precision and item difficulty hierarchies of the instrument were examined. The item-difficulty hierarchy was investigated to identify the easy and difficult items. We tested differential item functioning (DIF) for sex and age groups. Results : PCA revealed that the instrument met the unidimensionality assumption (eigenvalue = 1.78). Among the 12 items, item 2 was removed because of misfit (Infit MnSq = 1.33, Infit ZSTD = 5.05, Outfit MnSq = 1.56, Outfit ZSTD = 7.15). The remaining 11 items demonstrated a conceptual item-difficulty hierarchy. The person strata value was 3.10, which is equivalent to a reliability index value of 0.81. There was no DIF for the sex and age groups (DIF contrast <0.27). Conclusion : The findings indicated that the revised COPE-11 has adequate item-level psychometric properties and can accurately measure stress coping skills.