• Journal of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.118-131
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• 1995

The shock fracture analysis for the structures of navy vessels subject to underwater explosions or of high speed vessels frequently subject to impact loads has been carried out in two steps such as the global or macro analysis and the fine or micro analysis. In the macro analysis, Doubly Asymptotic Approximation(DAA) has been applied. The three main failure modes of structure members subject to strong shock loading are late time fracture mode such as plastic large deformation mainly due to dynamic plastic buckling, and the early time fracture mode such as tensile tearing failure or transverse shear failure. In this paper, the tensile tearing failure mode is numerically analyzed for the micro analysis by calculating the dynamic stress intensity factor $K_I(t)$, which shows the relation between stress wave and crack propagation on the longitudinal stiffener of the model. Especially, in calculating this factor, the numerical caustic method developed from shadow optical method of caustic well known as experimental method is used. The fully submerged vessel is adopted for the macro analysis at first, of which the longitudinal stiffener, subject to early shock pressure time history calculated in macro analysis, is adopted for the micro analysis.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.735-740
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• 2007

Purpose: Blowout fracture is an outward fracture of the orbital wall. That usually occurs at inferior or medial wall of the orbit. The main pathophysiology is high intraocular pressure derived from impact of trauma. Among the four orbital wall, the medial wall is thinnest and most vulnerable to trauma. Many kinds of methods were introduced for correction of medial orbital wall fracture. Recently, transnasal endoscopic reconstruction methods were widely used. Endoscopic methods had many advantages. However, we experienced some cases of postoperative maxillary sinusitis. This study was planned to find out the effectiveness of middle meatal antrostomy after endoscopic reconstruction of medial orbital wall fracture. Methods: This study was retrospective analysis of 28 patients who underwent transnasal endoscopic repair of medial orbital wall fracture. The 18 male and 10 female patients were ranged from 17 to 57 years of age(mean, 30.9 years). Among 28 patients, randomly selected 17 patients underwent middle meatal antrostomy as additional procedure by the same surgeon. After at least 12 months of follow-up period, we examined the nasal symptom, endoscopic and CT findings. Results: One patient complained of nasal obstruction in middle meatal antrostomy group and four patients complained nasal symptoms in non middle meatal antrostomy group. On the endoscopic findings, three patients of non middle meatal antrostomy group had continuous nasal discharge. But middle meatal antrostomy group had no abnormal endoscopic findings. The abnormal CT finding(abnormal mucosal hypertrophy) were detected in four patient of non middle meatal antrostomy group. There were no abnormal CT findings in middle meatal antrostomy group. The data were statistically significant at comparative study. Conclusion: Authors think that the middle meatal antrostomy has some advantages as a additional procedure of endoscopic reconstruction of medial orbital wall fracture. Especially, it is good at preventing postoperative maxillary sinusitis. But, more larger group and strict application of disease entity are need for correct evaluation of middle meatal antrostomy effect.

• Journal of Korea Water Resources Association
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• v.40 no.9
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• pp.735-742
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• 2007

In this study, a methodology which is based on segments and minimum outsets to estimate the reliability of a real water distribution system efficiently and accurately is suggested. The current reliability assessment models based on minimum cutset consider a pipe as only area impacted by a pipe failure which incurs underestimation of pipe failure impact. In contrary, the suggested methodology adopts "segment" and "unintended isolation" with the hydraulic pressure failure area to define the actual service interruption area in a water distribution system due to a pipe failure, which is different from the Previous reliability estimating methodologies. In addition, a minimum cutset is defined as a single segment incurring abnormal operating conditions and the success mode approach is used to account for the probability of multiple failure combinations of minimum outsets. The model considers numbers and locations of on-off valves when the service interruption area is defined. Once the methodology is applied to a real water distribution system, it is possible to define actual service interruption areas and using the defined areas, the reliability of the water distribution system is estimated reliably, compared with the previous reliability assessment methodologies.

• Nutrition Research and Practice
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• v.4 no.6
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• pp.522-527
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• 2010

Cardiovascular disease is a leading cause of death and disability and remains so in the future. The aim of this study was to detect the impact of a 6-month diet intervention on cardiovascular risk factors in postmenopausal Iranian women. It was a randomized controlled trial that carried out in the East Health Clinic in Ahvaz-Iran. This study started on June 2007 and was completed on May 2008. A total 64 healthy postmenopausal women recruited and randomly assigned to the intervention group (35) and control (29). Over the six months follow-up, the intervention group received five educational sessions (two face to face and three lecture discussion classes with slide demonstration) at the first month. These sessions were about menopause, cardiovascular disease and healthy diet. Every participant in the intervention group received one face to face education session at the $3^{rd}$ month, and also received a telephone call at the end of each month starting with the second month to remain on the diet. Pre-intervention and post-intervention anthropometric measurements, blood pressure, blood lipids and dietary intake were assessed. Data analyzed using the SPSS version 15. Descriptive (means and SD), univariate (paired-t test, Chi-Square and Independent T-test) and multivariate (GLM Repeated Measure) statistics were used. Participants in the diet group had significantly lower weight (-0.9 kg), body mass index (-0.4 $kg/m^2$), and fasting blood sugar (-4.5 mg/dl). The diet group significantly increased their daily intake of fiber (+2.3 g, P=0.05), decreased their intake of sodium (-28 mg, P=0.04), and consumption of fruit and vegetable ${\geq}$ 5 serving a day (80%, P=0.03) compared to the control group. Post menopausal women are at a greater risk for cardiovascular disease. Healthy diet using educational intervention can be an effective means of reducing cardiovascular risk in postmenopausal women.

• Journal of the Korean Society of School Health
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• v.12 no.1
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• pp.97-107
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• 1999

The purpose of the study was to ascertain the trends of future circumstances in primary education along with population change. These trends, which are subject to change in population and structure, have a great impact on the size and characteristics of primary school-aged children. Accordingly, it is imperative for the government to plan for future conditions involving primary education. The major findings of the study were as follows: 1. In the long-term primary school children aged 6-11, which accounted for 17.7% of the total population in 1970, will decline to 8.6% by the year 2000, 6.9% in 2020 and 6.4% in 2030. This drastic reduction in fertility rate is a direct result of pressure by the government to control population. 2. In 1996, the total number of classes in primary schools rose to 106,594. In the future, these numbers will actually decline. By 2003 the total number of classes will peak at 142,605, but until then drop off to 112,288 by 2030-a decrease of over 6,000. 3. The actual number of primary schools in 1997 totaled 5,721. This figure will reach its highest peak, 5,942, in 2003, but it is expected decrease later after declining by 1,263, it will bottom out at 4,679 in 2003. 4. The number of teachers at primary schools increased from 101,095 in 1970, 119, 064 in 1980, 136,800 in 1990 to 138,369 in 1995. Accordingly this means that the ratio of students to teaching staff changed for the better. By the year 2005, if teachers of specialty subjects (music, art, English, physical education) are assigned to every primary school with over 18 classrooms and the number of students per class is 30, it should improve educational surroundings. This is because it is expected that the population of primary school children will continue to grow until 2003 and then decrease. Thus, there is a need to maintain the number of primary school teachers between the years 2003 and 2030 so that the ratio of students to teachers will be reduced to 1/20.25. In considering factors related to migration which influence conditions of education, it is evident that changes have already begun. In the suburbs of Seoul, population shifts are causing overcrowding in classrooms. The government believes it would be inefficient to invest in education because fluctuating migration figures make it impossible. Accordingly, we have to be concerned about stabilizing the population throughout the entire country.

• Wind and Structures
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• v.23 no.6
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• pp.559-575
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• 2016

In order to investigate the influence of different blade positions on aerodynamic load and wind loads and load-effects of large scale wind turbine tower under the halt state, we take a certain 3 MW large scale horizontal axis three-blade wind turbine as the example for analysis. First of all, numerical simulation was conducted for wind turbine flow field and aerodynamic characteristics under different halt states (8 calculating conditions in total) based on LES (large eddy simulation) method. The influence of different halt states on the average and fluctuating wind pressure coefficients of turbine tower surface, total lift force and resistance coefficient, circular flow and wake flow characteristics was compared and analysed. Then on this basis, the time-domain analysis of wind loads and load-effects was performed for the wind turbine tower structure under different halt states by making use of the finite element method. The main conclusions of this paper are as follows: The halt positions of wind blade could have a big impact on tower circular flow and aerodynamic distribution, in which Condition 5 is the most unfavourable while Condition 1 is the most beneficial condition. The wind loads and load-effects of disturbed region of tower is obviously affected by different halt positions of wind blades, especially the large fluctuating displacement mean square deviation at both windward and leeward sides, among which the maximum response occurs in $350^{\circ}$ to the tower top under Condition 8; the maximum bending moment of tower bottom occurs in $330^{\circ}$ under Condition 2. The extreme displacement of blade top all exceeds 2.5 m under Condition 5, and the maximum value of windward displacement response for the tip of Blade 3 under Condition 8 could reach 3.35 m. All these results indicate that the influence of halt positions of different blades should be taken into consideration carefully when making wind-resistance design for large scale wind turbine tower.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.157-162
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• 2003

The sludge oils were produced necessarily in the ships operation, so that it will be the best way to manage the sludge oils inside ship itself from a viewpoint of the prevention of marine oil pollution from ship. The ultrasonic breaking systems which recycle the sludge oil from ship into usable oil to be brunt is recognized as a most possible recycling device. In this regards, the purpose of this study is to examine erosion damage on the SS400 specimen by cavitation and the effect of impact pressure generated from the demolition of the cavity of ultrasonic vibration in the marine sludge oil environment .. The erosion damage of specimen was investigated mainly on weight loss, weight loss rate and maximum erosion rate with variation of the oil temperature as well as the change of space between transducer horn and specimen. The experimental results showed that as the space between ultrasonic vibrator horn and specimen disk increased, the weight loss and weight loss rate decreased and the values were larger in SFO than in SLO. The experimental results can be useful to the development of sludge oil disposing systems and to consider a countermeasure for the prevention of erosion damages by cavitation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.1
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• pp.211-224
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• 2018

It is important to design tunnel support system considering the various loads acting on the tunnel because they have a direct impact on the stability of tunnels. In Korea, standardized support patterns are defined based on the rock mass classification system depending on the project, and it is stated that it should be modified appropriately considering the behavior of tunnel during construction. In this study, the tunnel support pattern optimization method is suggested based on the convergence-confinement method, earth pressure, axial force of rock bolt, and moment acting on the shotcrete. The length and spacing of the rock bolts and the thickness of the shotcrete were optimized by using the differential evolution algorithm (DEA) and the results were compared to the standard support pattern III for railway tunnel. Rock bolt length can be reduced and the installation interval can be widened for shallow tunnel. As the depth of tunnel increases, the thickness of shotcrete increases linearly. Therefore, the thickness of shotcrete should be thicker than the standard support pattern as the depth of tunnel increases to secure the stability of tunnel.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.1
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• pp.122-142
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• 2012

The importance of rainfed areas and animal agriculture on productivity enhancement and food security for economic rural growth in Asia is discussed in the context of opportunities for increasing potential contribution from them. The extent of the rainfed area of about 223 million hectares and the biophysical attributes are described. They have been variously referred to inter alia as fragile, marginal, dry, waste, problem, threatened, range, less favoured, low potential lands, forests and woodlands, including lowlands and uplands. Of these, the terms less favoured areas (LFAs), and low or high potential are quite widely used. The LFAs are characterised by four key features: i) very variable biophysical elements, notably poor soil quality, rainfall, length of growing season and dry periods, ii) extreme poverty and very poor people who continuously face hunger and vulnerability, iii) presence of large populations of ruminant animals (buffaloes, cattle, goats and sheep), and iv) have had minimum development attention and an unfinished wanting agenda. The rainfed humid/sub-humid areas found mainly in South East Asia (99 million ha), and arid/semi-arid tropical systems found in South Asia (116 million ha) are priority agro-ecological zones (AEZs). In India for example, the ecosystem occupies 68% of the total cultivated area and supports 40% of the human and 65% of the livestock populations. The area also produces 4% of food requirements. The biophysical and typical household characteristics, agricultural diversification, patterns of mixed farming and cropping systems are also described. Concerning animals, their role and economic importance, relevance of ownership, nomadic movements, and more importantly their potential value as the entry point for the development of LFAs is discussed. Two examples of demonstrated success concern increasing buffalo production for milk and their expanded use in semi-arid AEZs in India, and the integration of cattle and goats with oil palm in Malaysia. Revitalised development of the LFAs is justified by the demand for agricultural land to meet human needs e.g. housing, recreation and industrialisation; use of arable land to expand crop production to ceiling levels; increasing and very high animal densities; increased urbanisation and pressure on the use of available land; growing environmental concerns of very intensive crop production e.g. acidification and salinisation with rice cultivation; and human health risks due to expanding peri-urban poultry and pig production. The strategies for promoting productivity growth will require concerted R and D on improved use of LFAs, application of systems perspectives for technology delivery, increased investments, a policy framework and improved farmer-researcher-extension linkages. These challenges and their resolution in rainfed areas can forcefully impact on increased productivity, improved livelihoods and human welfare, and environmental sustainability in the future.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2699-2705
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• 2014

This study was to undertaken to investigate the impacts of AhR, CYP1A1, GSTM1 genetic polymorphisms on the R273G mutation in exon 8 of the tumor suppressor p53 gene (TP53) among polycyclic aromatic hydrocarbons (PAHs) exposed to coke-oven workers. One hundred thirteen workers exposed to PAH and 82 control workers were recruited. We genotyped for polymorphisms in the AhR, CYP1A1, GSTM1, and TP53 R273G mutation in blood by PCR methods, and determined the levels of 1-hydroxypyrene as PAH exposure marker in urine using the high pressure liquid chromatography assay. We found that the distribution of alcohol users and the urinary excretion of 1-OHP in the exposed workers were significantly higher than that of the control workers (p=0.004, p<0.001, respectively). Significant differences were observed in the p53 genotype distributions of smoking subjects (p=0.01, 95%CI: 1.23-6.01) and PAH exposure (p=0.008, 95%CI: 1.24-4.48), respectively. Further, significant differences were observed in the p53 exon 8 mutations for the genetic polymorphisms of Lys/Arg for AhR (p=0.02, 95%CI: 0.70-15.86), Val/Val for CYP1A1 (p=0.04, 95%CI: 0.98-19.09) and null for GSTM1 (p=0.02, 95%CI: 1.19-6.26), respectively. Our findings indicated that polymorphisms of PAH metabolic genes, such as AhR, CYP1A1, GSTM1 polymorphisms may interact with p53 genetic variants and may contribute to PAH related cancers.