• Maxillofacial Plastic and Reconstructive Surgery
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• v.17 no.4
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• pp.396-406
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• 1995

This is a clinical and retrospective study who sustained a total of 306 maxillofacial bone fracture and who were treated in our department between 1990-1994. This results were obtained as follows : 1. The ratio of men to women was 3.2 : 1. 2. The age frequency was the highest in the third decade(35%). That of man was the highest in the third decade but that of women in the fourth decade. 3. In respect of incidence, the number of patients has not been increased year after year. There were the highest frequency in September and the lowest frequency in January. 4. The most frequent cause of facial bone fracture was fall down(40.2%), traffic accident(28.1%), fist blow(20.9%), industrial accident(6.2%) and others in order. 5. The most common location of facial bone fracture was mandible(69%), maxillar with zygoma and zygoma in order of frequency. 6. The age frequency of mandible was the third decade(36.5%), the fourth decade(23.2%) and the fourth decade(22.2%) and the fifth decade(15.6%) in order. 7. In respect of incidence of associated injuries, the ratio of absence to presence was 0.7 : 1. 8. In 306 patients of facial bone fracture, the frequency of associated injuries was laceration, extrimities, chest in order.

• Nuclear Engineering and Technology
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• v.43 no.6
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• pp.531-546
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• 2011

The backward differentiation formula (BDF) method is applied to a three-dimensional reactor kinetics calculation for efficient yet accurate transient analysis with adaptive time step control. The coarse mesh finite difference (CMFD) formulation is used for an efficient implementation of the BDF method that does not require excessive memory to store old information from previous time steps. An iterative scheme to update the nodal coupling coefficients through higher order local nodal solutions is established in order to make it possible to store only node average fluxes of the previous five time points. An adaptive time step control method is derived using two order solutions, the fifth and the fourth order BDF solutions, which provide an estimate of the solution error at the current time point. The performance of the BDF- and CMFD-based spatial kinetics calculation and the adaptive time step control scheme is examined with the NEACRP control rod ejection and rod withdrawal benchmark problems. The accuracy is first assessed by comparing the BDF-based results with those of the Crank-Nicholson method with an exponential transform. The effectiveness of the adaptive time step control is then assessed in terms of the possible computing time reduction in producing sufficiently accurate solutions that meet the desired solution fidelity.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1137-1147
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• 2020

The discrete ordinates method (S_N) is one of the major shielding calculation method, which is suitable for solving deep-penetration transport problems. Our objective is to explore the available quadrature sets and to improve the accuracy in shielding problems involving strong anisotropy. The linear discontinuous finite-element (LDFE) quadrature sets based on the icosahedron (in short, ICLDFE quadrature sets) are developed by defining projected points on the surfaces of the icosahedron. Weights are then introduced in the integration of the discontinuous finite-element basis functions in the relevant angular regions. The multivariate secant method is used to optimize the discrete directions and their corresponding weights. The numerical integration of polynomials in the direction cosines and the Kobayashi benchmark are used to analyze and verify the properties of these new quadrature sets. Results show that the ICLDFE quadrature sets can exactly integrate the zero-order and first-order of the spherical harmonic functions over one-twentieth of the spherical surface. As for the Kobayashi benchmark problem, the maximum relative error between the fifth-order ICLDFE quadrature sets and references is only -0.55%. The ICLDFE quadrature sets provide better integration precision of the spherical harmonic functions in local discrete angle domains and higher accuracy for simple shielding problems.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.3
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• pp.44-58
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• 2017

The purpose of this study is to prove the Korean Internet company, Kakao's resilience capacity. For it, this paper reviews the previous literatures regarding Kakao's business models and discusses 'resilience' theory. Then, it organizes the research questions based on the theoretical background and explains the research methodology. It investigates the case of Kakao's business and organization. The case analysis shows that five levers of resilience are a good indicator for a successful platform business evolution. The five levers are composed of coordination, cooperation, clout, capability, and connection: First lever, coordination that makes the company to restructure its silo governance in order to respond to actual business flow starting from the basic asset like game and music content; second lever, cooperation where the firm provides creative people with playground for startups such as KakaoPage; third lever, clout where the company shares its data by opening its API of AI and chatbot to $3^{rd}$ party developers; fourth lever, capability where the firm establishes AI R&D center, KakaoBrain as the function of multi-domain generalist for developing diverse platforms tackling customer needs; and the last fifth lever, connection where the firm continues to expand its platform business to the peripheries, O2O businesses such as KakaoTaxi, KakaoOrder, KakaoPay, and KakaoBank. In conclusion, this study proposes Internet companies to be a resilient platform utilizing those five levers of resilience in order to form successful platform. This study contributes to the agile innovation of Internet platform with ecological sense.

• Journal of Preventive Medicine and Public Health
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• v.52 no.3
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• pp.200-204
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• 2019

On September 12, 2018, President Jae-In Moon announced the Comprehensive Plan for Lifelong Care for People with Developmental Disabilities, with representatives from the associated government branches (Ministry of Health and Welfare, Ministry of Education, and Ministry of Employment and Labor) in attendance. The goals of this plan are to provide health, medical, rehabilitative, special education, and social welfare services according to the life-stages of the affected individuals; to reduce parental pressure; to promote social interventions; and to enhance community-level participation in order to create a 'welfare society in harmony.' However, in order for the plan to succeed, additional efforts must be made in the following areas. First, an epidemiological survey is needed to understand the scale, prevalence, and incidence of developmental disabilities and to establish an evidence base to support policy development. Second, accurate definitions of developmental disabilities must be established in order to avoid policy discrimination based on impairment type and age. Third, personal evaluations to assess disabled individuals' unmet needs and customized service designs to deliver those needs are required. Fourth, the plan must fulfill the goals of accessibility and fairness that the government intends to provide. Fifth, the government should consider an integrated financial support system and to propose a detailed plan for monetary distributions. Finally, an integrated system that links health, medical, employment, educational, and welfare services must be constructed.

• Steel and Composite Structures
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• v.42 no.1
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• pp.75-90
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• 2022

The pointwise equilibrium polynomial (PEP) element considering local second-order effect has been widely used in direct analysis of many practical engineering structures. However, it was derived according to Euler-Bernoulli beam theory and therefore it cannot consider shear deformation, which may lead to inaccurate prediction for deep beams. In this paper, a novel beam-column element based on Timoshenko beam theory is proposed to overcome the drawback of PEP element. A fifth-order polynomial is adopted for the lateral deflection of the proposed element, while a quadric shear strain field based on equilibrium equation is assumed for transverse shear deformation. Further, an additional quadric function is adopted in this new element to account for member initial geometrical imperfection. In conjunction with a reliable and effective three-dimensional (3D) co-rotational technique, the proposed element can consider both member initial imperfection and transverse shear deformation for second-order direct analysis of frame structures. Some benchmark problems are provided to demonstrate the accuracy and high performance of the proposed element. The significant adverse influence on structural behaviors due to shear deformation and initial imperfection is also discussed.

• Journal of Elementary Mathematics Education in Korea
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• v.21 no.3
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• pp.531-546
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• 2017

This study explores the basis for determining priority among the four arithmetical operations in order to provide useful pedagogical content knowledge for teaching the order of operations. The study also discusses the perspective for viewing the order of operations. It presents the following five suggestions based on the results of the discussion. First, teachers should be made to realize that the same result can be obtained on calculation even when subtraction and division are performed first in mixed operations of addition and subtraction and mixed operations of multiplication and division. Second, teachers should understand why the rule of calculating sequentially from the left side of an equation has become customary. Third, teachers should be offered an explanation for the driver of the rule setting that multiplication takes precedence over addition in mixed operations of multiplication and addition. Fourth, the significance of the quantity within parenthesis must be emphasized to teachers. Fifth, teachers must gain an in-depth understanding about the order of operations by getting a description of all the customary and conceptual perspectives on the order of operations when describing the same in the teacher's guide.

• Korean Institute of Interior Design Journal
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• v.26 no.6
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• pp.81-96
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• 2017

This study aims at establishing a basic theory for the combination of architecture and movies by comparing the long-take technique of movies and the continuity of space, one of space composition principles, which is important in digital architecture based on Jacques Lacan's visual-art theory and finding common features and differences of them. The following is a summary of the conclusions. First, analyzing the long-take technique on the basis of Lacan's visual-art theory found that the subject of representation is scenes of movies and that staring shows features of narrative. Second, the long-take technique can be thought as a cinematic technique which tries to realize the real order beyond the symbolic order in real life through the process of continuous replication of replication of replication of a scene in one shot. Third, in contemporary architecture, which is compared to the long-take technique in the past, the inclined space of opened gaze is similar to the method which tries to realize architectural space of the reality which belongs to the symbolic order close to the real order which belong to significant in human unconsciousness. Fourth, the freeform continuous space of closed gaze, which can be compared to contemporary long take combined with computer graphic technology, has more difficulty in realizing the real order than the long-take technique in the past and inclined, continuous space as the feature which belongs to $signifi{\acute{e}}$ in human consciousness has been strengthened through the circulation which repeats and expands along an observer's movement. Fifth, when the contemporary long-take technique and freeform continuous space expand gaze which opens from the inside to the outside, it is considered that the space which is closer to the real order than the classic long-take technique and inclined continuous space can be created.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.5
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• pp.607-614
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• 2016

The objectives of the study were to estimate genetic parameters for milk production traits of Holstein cattle using random regression models (RRMs), and to compare the goodness of fit of various RRMs with homogeneous and heterogeneous residual variances. A total of 126,980 test-day milk production records of the first parity Holstein cows between 2007 and 2014 from the Dairy Cattle Improvement Center of National Agricultural Cooperative Federation in South Korea were used. These records included milk yield (MILK), fat yield (FAT), protein yield (PROT), and solids-not-fat yield (SNF). The statistical models included random effects of genetic and permanent environments using Legendre polynomials (LP) of the third to fifth order (L3-L5), fixed effects of herd-test day, year-season at calving, and a fixed regression for the test-day record (third to fifth order). The residual variances in the models were either homogeneous (HOM) or heterogeneous (15 classes, HET15; 60 classes, HET60). A total of nine models (3 orders of $polynomials{\times}3$ types of residual variance) including L3-HOM, L3-HET15, L3-HET60, L4-HOM, L4-HET15, L4-HET60, L5-HOM, L5-HET15, and L5-HET60 were compared using Akaike information criteria (AIC) and/or Schwarz Bayesian information criteria (BIC) statistics to identify the model(s) of best fit for their respective traits. The lowest BIC value was observed for the models L5-HET15 (MILK; PROT; SNF) and L4-HET15 (FAT), which fit the best. In general, the BIC values of HET15 models for a particular polynomial order was lower than that of the HET60 model in most cases. This implies that the orders of LP and types of residual variances affect the goodness of models. Also, the heterogeneity of residual variances should be considered for the test-day analysis. The heritability estimates of from the best fitted models ranged from 0.08 to 0.15 for MILK, 0.06 to 0.14 for FAT, 0.08 to 0.12 for PROT, and 0.07 to 0.13 for SNF according to days in milk of first lactation. Genetic variances for studied traits tended to decrease during the earlier stages of lactation, which were followed by increases in the middle and decreases further at the end of lactation. With regards to the fitness of the models and the differential genetic parameters across the lactation stages, we could estimate genetic parameters more accurately from RRMs than from lactation models. Therefore, we suggest using RRMs in place of lactation models to make national dairy cattle genetic evaluations for milk production traits in Korea.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.5
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• pp.1-10
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• 2002

This study is based on user requirements before the implementation of B2B order and delivery systems. For accurate and easy understanding of the user's requirements I have expressed my specifications in graphical method and to make use of multiple diagrams, I have used UML. In these specifications, I have implemented B2B order and delivery systems with the use of XML, with company 'N' which is domestic aluminum manufacturer as the study object. The results of this study are as follows. First, both a developer and a user can understand the problems associated with specifying study objects through this system. Second, the communication between developers and users is more effective using this system. Third programming became easier because or the formalized specifications of this system. Fourth, this system facilitates the rapid handling of marketing department and stock management. Fifth, order and reservation management became more rapid and accurate through the use of this system. Sixth, this system can help nate B2B order and delivery systems that can be direct transactions. Seventh, this system helps to reduce purchasing costs by allowing for the rapid and simple order and delivery of raw materials. Finally, this study emphasized the advertising effect of an aluminum vessel.