• Nuclear Engineering and Technology
• /
• 제56권10호
• /
• pp.4042-4049
• /
• 2024

A new automatic group structure optimization method based on the perturbation theory was proposed for the few-group structure in two-step nuclear design procedure for VHTR. It applies the sensitivity coefficient of the perturbation theory which includes not only the effect of the cross section on the multiplication factor but also the adjoint weighted reaction rate. The sensitivity coefficient of the fine group for the multiplication factor was calculated and the group boundary for a few-group can be determined so that the summation of the fine group sensitivity for a few-group should be evenly distributed over every few-group. This method was successfully implemented in the ABGO code. VHTR-350 and MiHTR 2D core were used to investigate the performance and applicability of the proposed method. The code generated the new group structures for two cores and the error of the multiplication and reaction rate by the new group structure was compared with the result by the fine group structure. The comparisons indicate that the new group structure by the proposed method can provide the multiplication factor and reaction rates comparable to the existing group structure and more accurate results than the group structure obtained using the Contributon theory.

• Nuclear Engineering and Technology
• /
• 제56권6호
• /
• pp.2019-2028
• /
• 2024

Advanced nuclear reactors, especially the newly developed small and micro-reactors have complex neutron spectrum, which makes the deterministic reactor core calculations sensitive to the energy group structure of few-group cross-sections. To avoid significantly increasing the cost of energy discretization in the core calculation, two energy group structures with 31 groups and 33 groups were adopted for typical thermal and fast reactor cores, respectively. Then, an adaptive scheme of group division for reactor cores with a medium neutron spectrum was proposed. The works were based on the full spectrum nuclear reactor analysis code SARAX/TULIP. An equivalent one-dimensional model of the core was proposed to capture the key neutron spectrum features of the reactor core. Such features were used to adaptively determine a few-group structure for the following reactor core calculations. Then, the neutron spectrum in different zones with more details was calculated. With this spectrum, the cross-sections were condensed into the determined energy groups. Three tests based on different neutron spectrum were calculated to verify the schemes. The results show that using the adaptive energy group division scheme, the following core calculation can meet the accuracy requirement of different reactors with different neutron spectra.

• 한국통신학회논문지
• /
• 제23권9A호
• /
• pp.2258-2270
• /
• 1998

Recently, the distributed processing environments provide various open multimedia serivces through telecommunication network and have been developing into information networking structure based on object oriented concepts and distributed systems which can apply new services with a few changes the existing networks. This paper proposes the object group model which is the collection of objects and can functionally and efficiently manage the individual object. this paper presents the analysis of the requirement and the function specifications to propose the object group model, and depicts the functional structure in details using its analysis. The goal of this paper is to decrease the complexity of the object's management and to voercome the limitations of among the components of object group for management and service functions based on our proposed the object group model and show interaction procedures to eTD (event tracing diagram)s and finally we design the object group model by TINA-ODL.

• 유통과학연구
• /
• 제13권9호
• /
• pp.19-27
• /
• 2015

Purpose - In a global economy, marketers are required to understand service quality from an international consumer viewpoint. Despite the increased need for cross-cultural research, few studies have developed service quality research international in scope. The present research aims to shed light on variations in airline service quality among international consumers. Research design, data, and methodology - Conducting crosscultural research, this study compares airline service quality variations, investigating an international consumer group and a Korean consumer group. T-test and factor analyses are applied to examine mean scores and factor structure of the airline service dimensions. Results - The results indicate there are significant differences in mean comparisons between the groups. The international consumers indicate significantly higher service perception scores than the Koreans. Further, we find that the factor structure of airline service quality diverges between the groups. The international group considers airline service quality in four dimensions, while Koreans consider it in two. Conclusions - The study sheds new light on international service variations and suggests that the field of airline service quality may differ by nations and/or cultures.

• Journal of applied mathematics & informatics
• /
• 제42권5호
• /
• pp.1039-1049
• /
• 2024

The aim of the present paper is to study the lifts of a golden structure to tangent bundles of order r. We proved that r-lift of the golden structure F in the tangent bundle of order r is also a golden structure. We have also proved some theorems on the projection tensor in the tangent bundle of order r. Later we have established prolongations of G-structures immersed in the golden structure to the tangent bundle of order r and 2. Finally, we constructed few examples of the golden structure that admit an almost para contact structure on the tangent bundle of order 3 and 4.

• 디지털융복합연구
• /
• 제10권4호
• /
• pp.217-222
• /
• 2012

그룹 통신은 인터넷을 통해 급속도로 발전 중이며, 그룹통신으로는 화상회의, 인스턴트 메시지, 데스크 탑 공유, 다양한 e-커머스등과 같은 응용프로그램들이 있다. 안전한 그룹통신을 위해서 그룹 키를 생성하여 통신 메시지를 암호화하여 교환함으로써 그룹통신의 기밀성을 보장할 수 있다. 본 연구에서는 그룹 키를 보다 안전하면서 효율적으로 생성하여 안전한 그룹통신에 기여하는데 그 목적이 있다.

• 아동학회지
• /
• 제25권2호
• /
• pp.59-69
• /
• 2004

The question addressed by the present research was whether repeated, careful reading of a few stories(Intensive Reading) is more effective than general, one-time reading of many stories(Extensive Reading). Unfamiliar stories were read to 105 kindergarten children from typewritten sheets of paper for 40 days(about 10 weeks). The Intensive Reading group heard 5 stories and the Extensive Reading group heard 40 stories. Effectiveness was measured by interest level during story telling and by narrative structure. Test scores were analysed by ANCOVA. No differences were found between the 2 groups; however, as a new area of study it could serve as a catalyst for research on story telling methods.

• Genomics & Informatics
• /
• 제20권4호
• /
• pp.48.1-48.7
• /
• 2022

Penalized regression has been widely used in genome-wide association studies for joint analyses to find genetic associations. Among penalized regression models, the least absolute shrinkage and selection operator (Lasso) method effectively removes some coefficients from the model by shrinking them to zero. To handle group structures, such as genes and pathways, several modified Lasso penalties have been proposed, including group Lasso and sparse group Lasso. Group Lasso ensures sparsity at the level of pre-defined groups, eliminating unimportant groups. Sparse group Lasso performs group selection as in group Lasso, but also performs individual selection as in Lasso. While these sparse methods are useful in high-dimensional genetic studies, interpreting the results with many groups and coefficients is not straightforward. Lasso's results are often expressed as trace plots of regression coefficients. However, few studies have explored the systematic visualization of group information. In this study, we propose a multi-level polar Lasso (MP-Lasso) chart, which can effectively represent the results from group Lasso and sparse group Lasso analyses. An R package to draw MP-Lasso charts was developed. Through a real-world genetic data application, we demonstrated that our MP-Lasso chart package effectively visualizes the results of Lasso, group Lasso, and sparse group Lasso.

• 호남수학학술지
• /
• 제32권1호
• /
• pp.177-192
• /
• 2010

We study the concepts of congruent number problems and elliptic curves. We research the structure of the group of elliptic curves and find out a method of the computation of L($E_n$, 1) and L'($E_n$, 1) by using SAGE program. In this paper, we obtain the first few congruent numbers for n ${\leq}$ 2500.

• Architectural research
• /
• 제13권1호
• /
• pp.17-24
• /
• 2011

Isogeometric solution of Poisson equation is provided. NURBS (NonUniform B-spline Surface) is introduced to express both geometry of structure and unknown field of governing equation. The terms of stiffness matrix and load vector are consistently derived with very accurate geometric definition. The validity of the isogeometric formulation is demonstrated by using two numerical examples such as square plate and L-shape plate. From numerical results, the present solutions have a good agreement with analytical and finite element (FE) solutions with the use of a few cells in isogeometric analysis.