• Proceedings of the Korean Information Science Society Conference
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• 2010.06b
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• pp.1-5
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• 2010

정렬 알고리즘에서 사용한 원소 간 비교횟수를 기준으로, 비교횟수가 많게 되는 순열을 최악의 인스턴스(worst-case instance)라 명명하고 이를 찾기 위해 유전 알고리즘(genetic algorithm)을 사용하였다. 잘 알려진 퀵 정렬(quick sort), 머지 정렬(merge sort), 힙 정렬(heap sort), 삽입 정렬(insertion sort), 쉘 정렬(shell sort), 개선된 퀵 정렬(advanced quick sort)에 대해서 실험하였다. 머지 정렬과 삽입 정렬에 대해 탐색한 인스턴스는 최악의 인스턴스에 거의 근접하였다. 퀵 정렬은 크기가 증가함에 따라 최악의 인스턴스 탐색이 어려웠다. 나머지 정렬에 대해서 찾은 인스턴스는 최악의 인스턴스인지 이론적으로 보장할 수 없지만, 임의의 1,000개 순열을 정렬해서 얻은 비교횟수들의 평균치보다는 훨씬 높았다. 본 논문의 최악의 인스턴스를 탐색하는 시도는 알고리즘의 성능 검증을 위한 테스트 데이터를 생성한다는 점에서 의미가 크다.

• Korean Journal of Remote Sensing
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• v.24 no.3
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• pp.267-272
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• 2008

Tree species-specific estimates with spacebome high-resolution imagery improve estimation of forest biomass which is needed to predict the long term planning for the sustainable forest management(SFM). This paper is a contribution to develop crown distinguishing coniferous species, Pinus densiflora and Pinus koraiensis, from QuickBird imagery. The proposed feature analysis derived from shape parameters and first and second-order statistical texture features of the same test area were compared for the two species separation and delineation. As expected, initial studies have shown that both formfactor and compactness shape parameters provided the successful differentiating method between the pine species within the compartment for single crown identification from spaceborne high resolution imagery. Another result revealed that the selected texture parameters - the mean, variance, angular second moment(ASM) - in the infrared band image could produce good subset combination of texture features for representing detailed tree crown outline.

• The Journal of Economics, Marketing and Management
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• v.2 no.1
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• pp.18-28
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• 2014

In this research we investigate the effect return on assets, return on equity, profit margin and earnings per share on working capital management. Current ratio and quick ratio used as proxies for working capital management. The research sample includes 451 year -firm of Tehran Stock Exchange (TSE) listed companies for period 2007-10. The multiple linear regressions were applied to test the research hypotheses. The results showed that, return on assets and earnings per share have a negative impact on working capital management. The results also show that earnings per share and profit margin positively associated with the firm performance.

• The korean journal of orthodontics
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• v.35 no.3 s.110
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• pp.216-226
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• 2005

The purpose of this study was to test and compare the accuracy and reliability of soft tissue profile predictions generated from two computer software programs (Quick Ceph Image $Pro^{TM}$ (ver 3.0) and $V-Ceph^{TM}$(ver 3.5)) for mandibular set-back surgery. The presurgical and postsurgical lateral cephalograms of 40 patients (20 males and 20 females) were traced on the same acetate paper with the reference taken as the cranial base outline. The presurgical skeletal outlines were digitized onto each computer program and the mandible was moved to mimic the expected surgical procedure with reverence to the mandibular anterior border and lower incisor position of the actual postsurgical skeletal outline. The soft tissue profile was generated and the amount and direction of skeletal movement was calculated with each software. The predicted soft tissue profile was compared to the actual postsurgical soft tissue profile. There were differences between the actual and the predicted surgical soft tissue profile charges in the magnitude and direction, especially the upper lip. lower lip and the soft tissue chin (P<0.05). Quick Ceph had more horizontal measurement errors and thickness errors for the upper lip and lower lip, but V-Ceph had more vertical measurement errors of the lower lip (P<0.05). There was a positive correlation between the prediction errors and the amount of mandibular movements in the vertical position of Sn, the horizontal position of Ls and the upper lip thickness for V-Ceph, and there was a negative correlation in the horizontal position and the thickness of the lower lip for Quick Ceph (P<0.05). However all of the Prediction errors of both imaging softwares were ranged within 3mm, and this was considered to be allowable clinically.

• Speech Sciences
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• v.13 no.2
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• pp.7-18
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• 2006

An aphasia screening test can serve a main purpose of differentiating aphasics from non-aphasic patients in a quick as well as efficient manner. As a preliminary study for developing a standardized aphasia screening test for Korean patients, we constructed an aphasia screening test constituting items from the Paradise' Korean version-the Western Aphasia Battery(P K-WAB). All test items were analyzed in order to extract items with optimal item discrimination and adequate item difficulty indices. From the results, we were able to select some items from each subtest with optimal results of discriminant function analysis for aphasic and normal control groups. It is expected, thus, that information on the item analysis could be utilized in developing a Korean aphasia screening test.

• Information Systems Review
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• v.3 no.2
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• pp.277-288
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• 2001

Of critical importance to the success of any e-commerce site are the two factors: rapid application development and quick response time. A three-tier architecture composed of presentation layer, business layer, and data access layer emerges to allow rapid changes in user interface, business logic, and database structures. Too often, such a logical three-tier architecture is considered as requiring a three-tier physical architecture: Web server, application server, and database server running on separate computers. Contrary to the common belief, a Web stress test reveals that the three-tier logical architecture implemented on a two-tier physical platform guarantees a quicker response time due to the reduction in cross-machine communications. This would lead business firms to economize their spending on e-commerce: increasing the number of physical servers to expedite transaction is not necessarily the best solution. Before selecting a particular hardware configuration, a Web stress test needs to be conducted to compare the relative merits of alternative physical architectures. Together with capacity planning, Web stress test emerges as a powerful tool to build robust, yet economical e-commerce sites.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.92-93
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• 2015

The main purpose of this paper is to present the dynamic test method developed for measuring the elastic modulus of sound insulating coat. The test setup was devised based on the theoretical natural frequency of a simply-supported beam subject to free transverse vibration. A stainless steel beam was tested and the result showed a good compliance with the standard value listed in literatures. The result indicates that the test set up can serve as a quick, economical and suitable scheme to test non self-supporting materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.702-709
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• 2018

A quick-hardened concrete track was developed to improve the aged ballasted track to a concrete track, and applied to earthworks and tunnels of main and urban railways. Rebars for reinforcement are not generally applied to prestressed concrete sleepers. On the other hand, many cracked sleepers have been observed in railroad sites. A wide sleeper, which is one of the main components of quick-hardened concrete track, should be structurally safe and crack-resistant in a ballasted and concrete track to avoid this problem. In particular, a wide sleeper manufactured by a post-tension method must have reinforcing bars applied to the rail-seat section. In this paper, static tests, dynamic tests, and fatigue tests were carried out to compare the flexural strength and crack resistance performance of a wide sleeper with and without reinforcing bars for a quick-hardened concrete track. As a result of the test, if some reinforcing bars are applied appropriately to the rail-seat section of a wide sleeper, it will be possible to prevent the occurrence of cracks, delay the expansion of the crack width, and the flexural fracture.

• Journal of the Korean Society for Railway
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• v.18 no.6
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• pp.543-551
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• 2015

Quick-hardening track (QHT) is a construction method which is used to change from old ballast track to concrete track. Sufficient time for construction is important, as the construction should be done during operational breaks at night. Most of the time is spent on exchanging the ballast layer. If it is possible to apply the ballast non-exchange type of quick-hardening track, it would be more effective to reduce the construction time and costs. In this paper, pouring materials with high permeability are suggested and a construction method involving a layer separation pouring process considering the void condition is introduced in order to develop ballast non-exchange type of QHT. The separate pouring method can secure the required strength because optimized materials are poured into the upper layer and the lower layer for each void ratio condition. To ensure this process, a rheology analysis was conducted on the design of the pouring materials according to aggregate size, the aggregate distribution, the void ratio, the void size, the tortuosity and the permeability. A polymer series was used as the pouring material of the lower layer to secure the void filling capacity and for adhesion to the fine-grained layer. In addition, magnesium-phosphate ceramic (MPC) was used as the pouring material of the upper layer to secure the void-filling capacity and for adhesion of the coarse-grained layer. As a result of a mechanics test of the materials, satisfactory performance corresponding to existing quick-hardening track was noted.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.6
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• pp.132-140
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• 2019

In this study, a specimen composed of columns, walls, beams, and slabs was fabricated to investigate the estimated reliability using nondestructive test method for the location of structural members of reinforced concrete single layer structures. And for accurate analysis in the comparison process with the existing estimation formula, we try to analyze the reliability through statistical approach by using error rate comparison and Confidence interval estimation. As a result, The average error rate of the core test was 18.8% compared with the result of estimating the compressive strength using the ultrasonic pulse velocity method. The average error rate of the core test results compared with the result of estimating the compressive strength using the rebound hardness method was 20.1%, confirming the field applicability. it is judged that the reliability of the compressive strength estimation can be derived from the wall member to make a quick and efficient structure safety diagnosis using the ultrasonic pulse velocity method. In addition, it is judged that the reliability of the compressive strength estimation can be derived from the beam member to make a quick and efficient structure safety diagnosis using the rebound hardness method.