• Journal of Navigation and Port Research
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• v.48 no.2
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• pp.104-108
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• 2024

This study investigates the relationship between national controlling fleets and the managerial performance of ship management companies in Korea. As industries clearly show interrelations between upstream and downstream entities , it is likely that the managerial performance of ship management companies in Korea is affected by the size of national fleet. Therefore, the present study analyzes the impact of Korean fleet size on the growth and the profitability of ship management firms. To this end, the performances of 10 major ship management companies in the period from 2012-2022 are examined through panel data regressions. The results indicate that the size of the national fleet has a positive impact on growth in both the assets and the sales of ship management companies. Specifically, the size of the Korean-flagged fleet is the most crucial factor, while that of the foreign-flagged fleet has no significant effect. In stark contrast to the findings regarding growth, the size of national fleet is found to have no significant impact on the profitability of ship management companies. This study's findings are expected to provide valuable implications informing both the managerial decision-making of ship management companies as well as policy-making for shipping and its related industries.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.463-469
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• 2013

In this study, I examine whether differences in the levels of stress exist with regard to the police department size. To accomplish this, a way ANOVA analysis of variance(One-way ANOVA) was conducted. As a result, a significant difference was found in Job stress and traumatic stress according to the department size and grade. Specifically, first, in the job stress level on the department size, the smaller department size was, the higher job stress level was and the bigger department size was, the lower job stress level was. Second, in the traumatic stress level on the department size, the smaller department size was, the higher traumatic stress level was and the bigger department size was, the lower traumatic stress level was. Third, in the job stress level on the department grade, the lower department grade was, the lower job stress level was and the higher department grade was, the higher job stress level was. Fourth, in the traumatic stress level on the department grade, the lower department grade was, the lower traumatic stress level was and the higher department grade was, the higher traumatic stress level was.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.714-719
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• 2017

The controlled synthesis of inorganic materials with a specific size and morphology is an important factor in the development of new materials in many fields, such as nanoparticles, medicine, electronics, semiconductors, pharmaceutical sand cosmetics. Solution crystallization is one of the most widely used separation processes in the chemical and pharmaceutical industries. Calcium carbonate has attracted a great deal of attention in industry because of its numerous applications. The mean crystal size, crystal size distribution and morphology are important factors in the continuous crystallization process. In this study, the continuous crystallization of calcium carbonate by the calcium chloride process was investigated. The mean crystal size and crystal size distribution data were obtained by a particle size analyzer. The morphological imaging of the crystalswasper formed by SEM. Under steady state operation, the mean crystal size change was small, but increasing the input concentration and mixing rate increased the crystal size. In this operation, some aragonite was found, but the main crystal phase was calcite.

• Magazine of the Korea Concrete Institute
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• v.2 no.1
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• pp.91-100
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• 1990

In most of the structural members with initial cracks(or initial notches), the strength tends to decmase as the member size increases. This phenomenon is known as size effect. Among the structural materials of glass, metal or concrete, etc., concrete represents the size effect even without initial crack. According to the previous size effect law, the concrete mem¬ber of very large size can resist little stress. Actually, however, even the large size member can resist some stress if there is no initial crack made artificially, consequently showing a rather milder strength reduction compared to the severe strength reduction by tbe previously derived size effect law. In this study, the theoretical size effect law previously derived by Z.P. Bazant was discussed based on nonlinear fracture mechanics of concrete structures With dissimilar initial cracks, and the prediction models are proposed by regression analysis with the existing test data of more large size speciments for splitting tensile strength, shear strength and uniaxial compressive strength tests.

• Journal of the Korean Ceramic Society
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• v.54 no.6
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• pp.506-510
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• 2017

One of the characteristics of polycrystalline graphene that determines its material properties is grain size. Mechanical properties such as Young's modulus, yield strain and tensile strength depend on the grain size and show a reverse Hall-Petch effect at small grain size limit for some properties under certain conditions. While there is agreement on the grain size effect for Young's modulus and yield strain, certain MD simulations have led to disagreement for tensile strength. Song et al. showed a decreasing behavior for tensile strength, that is, a pseudo Hall-Petch effect for the small grain size domain up to 5 nm. On the other hand, Sha et al. showed an increasing behavior, a reverse Hall-Petch effect, for grain size domain up to 10 nm. Mortazavi et al. also showed results similar to those of Sha et al. We suspect that the main difference of these two inconsistent results is due to the different modeling. The modeling of polycrystalline graphene with regular size and (hexagonal) shape shows the pseudo Hall-Petch effect, while the modeling with random size and shape shows the reverse Hall-Petch effect. Therefore, this study is conducted to confirm that different modeling is the main reason for the different behavior of tensile strength of the polycrystalline structures. We conducted MD simulations with models derived from the Voronoi tessellation for two types of grain size distributions. One type is grains of relatively similar sizes; the other is grains of random sizes. We found that the pseudo Hall-Petch effect and the reverse Hall-Petch effect of tensile strength were consistently shown for the two different models. We suspect that this result comes from the different crack paths, which are related to the grain patterns in the models.

• The Journal of Korean Physical Therapy
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• v.33 no.5
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• pp.211-216
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• 2021

Purpose: The main purpose of this meta-analysis was to identify the degree of effect size and variables for the impact of manual physical therapy on the improvement in the range of motion of frozen shoulder patients. Methods: This study collected 8 studies published between 1st January 2010 and 31st December 2020. The analysis of the results verified 49 effect size data and the random effect model was chosen. Results: First, the full case showed the largest mean effect size of 2.485 (p<0.001). Second, the size of the effect based on manual therapy and modality therapy showed an effect size of 4.178 (p<0.001). Third, the outcome group included 6 variables. The external rotation (2.818) variable group showed the largest mean effect size, followed by internal rotation (2.748), flexion (2.643), abduction (2.356), and adduction (2.356). Six outcomes were significant and the mean effect sizes of all the varied groups were above large size. The number of participants showed a 20 or less effect size of 2.478 (p>0.737). The number of intervention periods showed 4 weeks 20 or more effect size of 2.782 (p>0.294). Finally, the 'Trim and Fill' result confirmed that the calibration effect size was 1.471 (p<0.001). Conclusion: This study verified that manual physical therapy had a substantial effect on the improvement of the range of motion of patients with frozen shoulders and that the effects were dependent on the methods of outcomes.

• Journal of radiological science and technology
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• v.44 no.3
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• pp.183-187
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• 2021

The field size of the lumbar spine X-ray examination, which belongs to the most frequent examination in general radiography, is 5 times wider than the width of the lumbar spine. Exposure index (EI) as per International Electrotechnical Commission has a proportional relationship with the dose incident on the image receptor for clinical protocols in addition to RQA5, which is a calibration beam quality. In this study, the effectiveness of the set field size was evaluated through the change of EI according to the size of field during lumbar spine X-ray examinations. Lumbar anterior-posterior and lateral examinations was performed using a whole-body phantom, and the national average exposure conditions of Korea investigated in 2017 were introduced for the X-ray exposure. As a result of comparing the EI displayed on the console of digital radiography system for the three field size in ① 18 × 36 cm2 ② 25 × 36 cm2 ③ 36 × 36 cm2, the EI values showed a tendency to increase as the field size increased. Since the patient dose, such as organ dose around the lumbar spine, increases as the field size becomes larger, thus, if the EI obtained from the field size at a level that does not interfere with diagnosis is set as a reference, the effectiveness of the field size can be evaluated through the EI displayed on the console when the lumbar spine X-ray examination is conducted.

• Fashion & Textile Research Journal
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• v.6 no.6
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• pp.756-764
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• 2004

The purpose of this study is to analyze of size and patterns of ready to wear basic for middle age women. For this purpose, I select 9 brands and analyze the basic skirts size system marketed in 2002 spring in Korea. To study the actual size system, I have compared size labeling, which I researched, with Korean Industrial Standard Size Chart. And I also have compared body measurement with the product size. To study the pattern, I have classified the composition of the skirt into 24 items. The different result shows between this study and Korean Industrial Standard Size Chart. The waist circumference is smaller than it should be, and the hip circumference is larger than it should be. As I have examined the body measurement and the product size, variability of the waist circumference depends on the location of the waistline. For the hip circumference, I have found that both the body measurement and the product size are same, or the product size is smaller than the body measurement. Both cases have been found to be over 67%. I have classified the analysis of the pattern into four components; circumference, relevance to waist line, dart, and length. For the waist circumference, the same size of the front and the back is 44.4%, and making the front larger is 44.4% also. In the hip circumference, the identical size of the front and the back is 66.7% and the larger size of back is 22.2%. Regarding darts placement, it is moved to the side lines from the middle of 1/2 of waist lines, dart intake was 1.3~3.2 cm, the length of darts is 7.2~12.7 cm.

• Korean Journal of Materials Research
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• v.23 no.2
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• pp.81-88
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• 2013

In this study, using a tin chloride solution as the raw material, a nano-sized tin oxide powder with an average particle size below 50 nm is generated by a spray pyrolysis process. The properties of the tin oxide powder according to the nozzle tip size are examined. Along with an increase in the nozzle tip size from 1 mm to 5 mm, the generated particles that appear in the shape of droplets maintain an average particle size of 30 nm. When the nozzle tip size increases from 1 mm to 2 mm, the average size of the generated particles is around 80-100 nm, and the ratio of the independent particles with a compact surface structure increases significantly. When the nozzle tip size is at 3 mm, the majority of the generated particles maintain the droplet shape, the average size of the droplet-shaped particles increases remarkably compared to the cases of other nozzle tip sizes, and the particle size distribution also becomes extremely irregular. When the nozzle tip size is at 5 mm, the ratio of droplet-shaped particles decreases significantly and most of the generated particles are independent ones with incompact surface structures. Along with an increase in the nozzle tip size from 1 mm to 3 mm, the XRD peak intensity increases, whereas the specific surface area decreases greatly. When the nozzle tip size increases up to 5 mm, the XRD peak intensity decreases significantly, while the specific surface area increases remarkably.

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.11-17
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• 2013

The life cycle of butterflies is closely related to the growth of food plants and, through a prolonged coevolutionary process, has undergone an ecological adaptation. So, it is important that control the egg-laying number and place to secure enough food plant by female adult to guarantee the survival of the larvae. To study whether oviposition control of the Luehdorfia puziloi takes into greater consideration food plant leaf biomass or leaf abundance, correlation among the egg cluster size, the leaf size, and the number of leaves around egg clusters was investigated. According to the results, the egg clusters size exhibited positive correlation with the leaf size of food plants on which eggs had been laid but did not do so with the number of surrounding leaves. In addition, the number of egg clusters laid exhibited positive correlation with the number of surrounding food plant leaves but not with the leaf size on which eggs had been laid. Consequently, for the Luehdorfia puziloi, the females' recognition of the leaf size seems to be the most important factor in the egg cluster size, and the number of egg clusters had positive correlation with food plant density per unit area.