• Journal of Korea Spatial Information System Society
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• v.7 no.2 s.14
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• pp.57-66
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• 2005

The Interconnecting Highways problem is an abstract of many practical Layout Design problems in the areas of VLSI design, the optical and wired network design, and the planning for the road constructions. For the road constructions, the shortest-length road layouts that interconnect existing positions will provide many more economic benefits than others. That is, finding new road layouts to interconnect existing roads and cities over a wide area is an important issue. This paper addresses an approximation scheme that finds near optimal road layouts for the Interconnecting Highways problem which is NP-hard. As long as computational resources are provided, the near optimality can be acquired asymptotically. This implies that the result of the scheme can be regarded as the optimal solution for the problem in practice. While other approximation schemes can be made for the problem, this proposed scheme provides a big merit that the algorithm designed by this scheme fits well to given problem instances.

• Journal of Conservation Science
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• v.11 no.1 s.14
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• pp.28-37
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• 2002

The cleaning in conservation treatment of cultural heritage is very important process. For the best conservation treatment of cultural heritage, except having a good detergency, the cleaning agent must be able to keep the heritage from the secondary deposition and re-soiling, damage and etc. In this paper, the dust (lichen, algae, dust, etc.) on the surface of stone made heritage was treated with some kinds of solvents and analyzed with FT-IR to develop a cleaning agent for stone made cultural heritage. And the cleaning ability to the dust and the corrosion ratio to the granite of the cleaning agent was investigated. Nonionic surfactants were good for treatment of stone-made cultural heritage. The reason is that nonionic surfactants are stable in acidic solution, and possess low reactivity with the compound of stone and low possibility to the second contamination, and build up the reactivities of acids and oxidants. A new cleaning agent composed with $H_2O_2/HF/NP-10$ shows a good cleaning ability for the conservation treatment of stone made cultural heritage.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.69-77
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• 2019

In this study, we evaluated the mechanical properties and nitrogen oxides removal characteristics according to the type and incorporation rate of the photocatalyst and investigated the method of separated placement for the production of economical and efficient photocatalyst concrete. As a result, when the photocatalyst incorporation rate was 5%, the highest compressive strength and elastic modulus were measured. As a result of evaluating the nitrogen oxides removal performance by the photocatalytic reaction, as the photocatalyst incorporation rate increased, the nitrogen oxide removal rate increased. At this time, the nitrogen oxides removal performance of photocatalyst P-25 was better than the NP-A. In consideration of economic efficiency, we have provided a method of separated placement for casting a constant thickness of concrete surface with photocatalyst concrete and evaluated the integrated performance at this time. As a result, it appears to be equal to or higher than mechanical performance and durability performance as compared with Plain, and it is judged that the integrated behavior is satisfied.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.440-440
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• 2011

We report on the non-volatile memory characteristics of a bistable organic memory (BOM) device with Au nanoparticles (NPs) embedded in a conducting poly N-vinylcarbazole (PVK) colloids hybrid layer deposited on flexible polyethylene terephthalate (PET) substrates. Transmission electron microscopy (TEM) images show the Au nanoparticles distributed isotropically around the surface of a PVK colloid. The average induced charge on Au nanoparticles, estimated using the C-V hysteresis curve, was large, as much as 5 holes/NP at a sweeping voltage of ${\pm}3$ V. The maximum ON/OFF ratio of the current bistability in the BOM devices was as large as $1{\times}105$. The cycling endurance tests of the ON/OFF switching exhibited a high endurance of above $1.5{\times}105$ cycles and a high ON/OFF ratio of ~105 could be achieved consistently even after quite a long retention time of more than $1{\times}106$ s.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.23-30
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• 1980

Experiments were conducted to know N, P, and K top dressing effects on yield and other agronomic characters of rice plants grown in 5-year differently fertilized soils. Four levels of nitrogen, 0, 1.2, 2.4, and 3.6kg/10a, were applied 32 days before heading in 5-year non-fertilized and PK applied plots. Four levels of P_2 $O_{5}$ and K_2 O of 0, 4, 8 and 12kg/l0a were applied 40 days before heading in 5-year NK and NP applied plots, respectively. 1. Heading was delayed by seven days in 5-year non-fertilized and PK applied plots compared to NK, NP, or NPK applied plots where nitrogen was applied as basal. However, in 5-year non-fertilized and PK applied plots heading was delayed from 1 to 4 days as amounts of nitrogen top dressing increased. Phosphorus and potassium did not affect heading date of rice plants. 2. In 5-year non-fertilized plot grain yield increased as amounts of nitrogen top dressing increased up to 2.4kg/l0a due to both increased number of panicles per hill and spikelets per panicle. However, in 5-year PK applied plot amounts of nitrogen top dressing did not affect grain yield; the number of panicle per hill increased, but the percentage of ripened grains and grain weight tended to decrease as nitrogen levels increase. 3. The number of panicle/maximum tillers ratio in percentage increased markedly as amounts of nitrogen top dressing increased in 5-year non-fertilized and PK applied plots with maximum value of 130% on the basis of maximum tillers at vegetative stage. 4. Top dressing of phosphorus and potassium did not affect yield and other agronomic characters in NK and NP applied plots.

• Korean Journal of Radiology
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• v.22 no.12
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• pp.1996-2005
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• 2021

Objective: To investigate the multidetector computed tomography (MDCT) features of fumarate hydratase-deficient renal cell carcinoma (FH-deficient RCC) with germline or somatic mutations, and compare them with those of papillary type II RCC (pRCC type II). Materials and Methods: A total of 24 patients (mean ± standard deviation, 40.4 ± 14.7 years) with pathologically confirmed FH-deficient RCC (15 with germline and 9 with somatic mutations) and 54 patients (58.6 ± 12.6 years) with pRCC type II were enrolled. The MDCT features were retrospectively reviewed and compared between the two entities and mutation subgroups, and were correlated with the clinicopathological findings. Results: All the lesions were unilateral and single. Compared with pRCC type II, FH-deficient RCC was more prevalent among younger patients (40.4 ± 14.7 vs. 58.6 ± 12.6, p < 0.001) and tended to be larger (8.1 ± 4.1 vs. 5.4 ± 3.2, p = 0.002). Cystic solid patterns were more common in FH-deficient RCC (20/24 vs. 16/54, p < 0.001), with 16 of the 20 (80.0%) cystic solid tumors having showed typical polycystic and thin smooth walls and/or septa, with an eccentric solid component. Lymph node (16/24 vs. 16/54, p = 0.003) and distant (11/24 vs. 3/54, p < 0.001) metastases were more frequent in FH-deficient RCC. FH-deficient RCC and pRCC type II showed similar attenuation in the unenhanced phase. The attenuation in the corticomedullary phase (CMP) (76.3% ± 25.0% vs. 60.2 ± 23.6, p = 0.008) and nephrographic phase (NP) (87.7 ± 20.5, vs. 71.2 ± 23.9, p = 0.004), absolute enhancement in CMP (39.0 ± 24.8 vs. 27.1 ± 22.7, p = 0.001) and NP (50.5 ± 20.5 vs. 38.2 ± 21.9, p = 0.001), and relative enhancement ratio to the renal cortex in CMP (0.35 ± 0.26 vs. 0.24 ± 0.19, p = 0.001) and NP (0.43 ± 0.24 vs. 0.29 ± 0.19, p < 0.001) were significantly higher in FH-deficient RCC. No significant difference was found between the FH germline and somatic mutation subgroups in any of the parameters. Conclusion: The MDCT features of FH-deficient RCC were different from those of pRCC type II, whereas there was no statistical difference between the germline and somatic mutation subgroups. A kidney mass with a cystic solid pattern and metastatic tendency, especially in young patients, should be considered for FH-deficient RCC.

• Korean Management Science Review
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• v.12 no.2
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• pp.77-87
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• 1995

In this paper we develop an efficient heuristic algorithm for the problem of scheduling n sequence-dependent jobs on a basic processor to minimize makespan. Efficient solution methods are already known for the sequence- independent case. But for the sequence-dependent case, this problem belongs to a set of strong NP-complete problems. We present a heuristic which is similar to shortest setup time heuristic but opportunity cost of setup time rather than shortest setup time is used for choosing next job. This heuristic algorithm has same computational complexity and worst case ratio as the shortest setup time heuristic. We used Wilcoxon signed rank test to show that our heuristic is superior to nearest setup time heuristic in term of average behavior.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.17-35
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• 1997

This paper considers the efficient design of routing path and wavelength assignment in the single-hop WDM optical transport networks. The connection demands between node-pairs are given and a connection between a pair of nodes must be made by only one lightpath. It is assumed that no wavelength conversion is allowed and the physical topology of the network and the number of available wavelengths of a physical link are also given. This paper proposes the method to route a path and assign a wavelength to the path, which guarantees fairness to every node pair. In order to guarantee fairness and maximize connections, an optimization model is established, which successively maximizes minimum connection ratio to the demand of each node pair. A heuristic algorithm with polynomial iterations is developed for the problem since the problem is NP-hard. The heuristic algorithm is implemented and applied to the networks with real problem sizes. The results of the application are compared with GAMS/OSL.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.3
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• pp.222-229
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• 2003

In this paper, we address a layout design problem, PTN[2], for determining an appropriate 2-class-based dedicated storage layout in a class of unit load storage systems. Our strong conjecture is that PTNI2] is NP-hard. Restricting PTN[2], we provide three solvable cases of PTN[2] in which an optimal solution to the solvable cases is one of the partitions based on the PAI(product activity index)-nonincreasing ordering. However, we show with a counterexample that a solution based on the PAI-non increasing ordering does not always give an optimal solution to PTN[2]. Utilizing the derived properties, we construct an effective heuristic algorithm for solving PTN[2] based on a PAI-non increasing ordering with performance ratio bound. Our algorithm with O($n^2$) is effective in the sense that it guarantees a better class-based storage layout than a randomized storage layout in terms of the expected single command travel time.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.137-139
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• 2003

As a part of numerical and experimental research works for the prediction and improvement of ship's maneuvering performance, a study on the performance analysis of two different rudders has been carried out. While the planform shape and the aspect ratio of the rudders have been fixed, section shape has been changed. Conventional type of HMRI NP section and special type of dolphin-tail section have been employed. Performances of the rudders have been investigated by using CFD and compared with experimental data obtained in a wind tunnel. A commercial CFD program has been used to solve the RANS equations. Two-equation k-ro model has been applied to close the governing equations. Block-structured grids are used in the numerical calculation. Based upon the calculation results, the rudder with dolphin-tail section has shown a possibility of significantly improving rudder performance if utilized as the section of ship rudders.