• Journal of the Korean Operations Research and Management Science Society
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• v.12 no.1
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• pp.139-139
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• 1987

This study addresses basic requirements for mathematical programming software, discusses considerations in designing these software, implementation issues facing in these types of applications development, and shows some examples of codes being developed in the course. This type of projects requires long and ever-changing evolutionary phases. The experience is therefore, valuaable in suggesting some useful hints which may be salvaged for similar projects as well as providing reusable codes. In particular, scanning and parsing the free-format inputs, symbol table management, mixed-language programming, and data structures dealing with large sparse matrices are indispensable to many management science software development. Extensions to be made are also discussed.

• Asian Journal of Turfgrass Science
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• v.10 no.2
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• pp.117-124
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• 1996

One new cellular slime mold, Dicivostelium valenstemmun sp. n. Shim et Chang, is isolated from the fermentation layer of soils in the cool temperate forests of Surak mountain, Korea. This species has the sori and sorophore yellow-pigmented, and sparse or irregular branches. And it is characterized by tall and robust sorocarps, well-form basal disks, mucoroides-type aggregations and large spores. This species has sorophores gradually tapering from bases to tips, simple capi- tate sorophore tips and conical bases. When prostrates on the plates, it has sparsely clavate bases. Spores are considerably large, 6.8~9.9 x 3.4~5.1 $\mu$m(avg. 8.5 x 4.1 $\mu$m), L /W index l.84~2.43(avg. 2.07) without polar granules. Key words: Diccyostelium valeustemmum, Cool temperate forests, Surak mountain.

• Bulletin of the Korean Mathematical Society
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• v.51 no.4
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• pp.1229-1240
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• 2014

In this paper we provide three results involving large Schr$\ddot{o}$der paths. First, we enumerate the number of large Schr$\ddot{o}$der paths by type. Second, we prove that these numbers are the coefficients of a certain symmetric function defined on the staircase skew shape when expanded in elementary symmetric functions. Finally we define a symmetric function on a Fuss path associated with its low valleys and prove that when expanded in elementary symmetric functions the indices are running over the types of all Schr$\ddot{o}$der paths. These results extend their counterparts of Kreweras and Armstrong-Eu on Dyck paths respectively.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.53.3-53.3
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• 2017

While quasars are sparse in number density, they reside at relatively high-redshift as compared to galaxies. Hence, they are likely to be less non-linearly evolved than the galaxy population, and thus have a distribution that more closely mirrors the primordial density field. Therefore, they offer an intriguing opportunity to search for primordial non-Gaussianity (PNG). To this end, the 3-point correlation function (3PCF) is an excellent statistical tool to detect departures from Gaussianity, vanishing for a Gaussian field. In this work, we will make the first-ever measurement of the large-scale quasar 3PCF from the SDSS-IV DR14 quasar sample (spanning the largest volume to-date) to place constraints on PNG through the usual f_NL-type parametrization. This work will use the order N^2-time 3PCF algorithm of Slepian & Eisenstein (2015), with N the number of objects.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.433-435
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• 2007

Geographic wireless sensor networks use position information for Greedy routing. Greedy routing works well in dense network where as in sparse network it may fail and require the use of recovery algorithms. Recovery algorithms help the packet to get out of the communication void. However, these algorithms are generally costlier for resource constrained position based wireless sensor type networks. In the present work, we propose a Void Avoidance Algorithm (VAA); a novel idea based on virtual distance upgrading that allows wireless sensor nodes to remove all stuck nodes by transforming the routing graph and forward packet using greedy routing only without recovery algorithm. In VAA, the stuck node upgrades distance unless it finds next hop node which is closer to the destination than itself. VAA guarantees the packet delivery if there is a topologically valid path exists. NS-2 is used to evaluate the performance and correctness of VAA and compared the performance with GPSR. Simulation results show that our proposed algorithm achieves higher delivery ratio, lower energy consumption and efficient path.

• Current Optics and Photonics
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• v.5 no.5
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• pp.562-575
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• 2021

As a new type of spectrometer, that based on filters with different transmittance features attracts a lot of attention for its advantages such as small-size, low cost, and simple optical structure. It uses post-processing algorithms to achieve target spectrum reconstruction; therefore, the performance of the spectrometer is severely affected by noise. The influence of noise on the spectral reconstruction results is studied in this paper, and suggestions for solving the spectral reconstruction problem under noisy conditions are given. We first list different spectral reconstruction methods, and through simulations demonstrate that these methods show unsatisfactory performance under noisy conditions. Then we propose to apply the gradient projection for sparse reconstruction (GRSR) algorithm to the spectral reconstruction method. Simulation results show that the proposed method can significantly reduce the influence of noise on the spectral reconstruction process. Meanwhile, the accuracy of the spectral reconstruction results is dramatically improved. Therefore, the practicality of the filter-based spectrometer will be enhanced.

• Journal of Forest and Environmental Science
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• v.32 no.4
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• pp.377-383
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• 2016

We obtained a total of 36 GPS coordinates of the seven bat species of Rhinolophus ferrumequinum, Myotis ikonnikovi, M. nattereri, M. petax, Murina ussuriensis, Plecotus auritus, and Pipistrellus abramus. Characteristics of forests (forest type, age class, DBH class and crown density), terrain (aspect, slope and distance from mountain stream) and disturbance factors (distance from human residential areas and distance from cultivated areas) that bats have used as their habitats were revealed from the GIS analysis based on GPS coordinates of the 36 positions that bats were found. The bats-preferred forest type is broad-leaf forests (43%) with the trees of the 2th (31%) and 5th (31%) age class, the trees of sapling (36%) and large DBH class (31%), and sparse crown density (67%). Bats prefer the slop direction of the east (39%), the gradient below $15^{\circ}$ (61%), the ranges within 200 m from the mountain streams (92%), the ranges within 200 m near roads (89%), the ranges of 200-400 m from human residential areas (28%), and the ranges within 200 m from cultivated areas (36%).

• Imaging Science in Dentistry
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• v.43 no.4
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• pp.253-259
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• 2013

Purpose: Radiographs is an integral part of patient management in dentistry, despite their detrimental effects. As the literature pertaining to radiation protection among Indian dental practitioners is sparse, exploring such protection is needed. Materials and Methods: All private dental practitioners in Mangalore, India were included in the study. A structured, pre-tested, self-administered questionnaire was employed to assess the knowledge, attitudes, practices, previous training, perceptions towards the need to spread awareness, and willingness to gain and implement knowledge about radiation hazards and protection. Information regarding each respondent's age, gender, education, and type and duration of practice was collected. Results: Overall, 87 out of 120 practitioners participated in the study. The mean knowledge, attitude, and practice scores were $9.54{\pm}2.54$, $59.39{\pm}7.01$, and $5.80{\pm}3.19$, respectively. Overall, 25.3% of the respondents had undergone training in radiation protection, 98.9% perceived a need to spread awareness, and 94.3% were willing to improve their knowledge. Previous training showed a significant correlation with age, sex, and duration of practice; attitude was significantly correlated with education and type of practice; and knowledge scores showed a significant correlation with type of practice. Conclusion: Although the knowledge and practices of respondents were poor, they had a positive attitude and were willing to improve their knowledge. Age, sex, and duration of practice were associated with previous training; education and type of practice with attitude scores; and type of practice with knowledge scores. The findings of this study suggest a policy is needed to ensure the adherence of dental practitioners to radiation protection guidelines.

• The Korean Journal of Applied Statistics
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• v.35 no.2
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• pp.229-250
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• 2022

Since the publication of Markowitz's (1952) mean-variance portfolio model, research on portfolio optimization has been conducted in many fields. The existing mean-variance portfolio model forms a nonlinear convex problem. Applying Dantzig's linear programming method, it was converted to a linear form, which can effectively reduce the algorithm computation time. In this paper, we proposed a Dantzig perturbation portfolio model that can reduce management costs and transaction costs by constructing a portfolio with stable and small (sparse) assets. The average return and risk were adjusted according to the purpose by applying a perturbation method in which a certain part is invested in the existing benchmark and the rest is invested in the assets proposed as a portfolio optimization model. For a covariance estimation, we proposed a Gaussian kernel weight covariance that considers time-dependent weights by reflecting time-series data characteristics. The performance of the proposed model was evaluated by comparing it with the benchmark portfolio with 5 real data sets. Empirical results show that the proposed portfolios provide higher expected returns or lower risks than the benchmark. Further, sparse and stable asset selection was obtained in the proposed portfolios.

• Parasites, Hosts and Diseases
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• v.38 no.1
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• pp.9-15
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• 2000

A scanning electron microscopic study was performed on the surface ultrastructure of metacercariae and adults of Metagonimus takahashii. Metacercariae were collected from the scale of crucian carp (Carassius auratus) , and adult flukes were harvested 1-4 weeks after infection to rats. In excysted metacercariae. the oral sucker had type I (numerous) and type II (seven in total) sensory papillae. Tegumental spines were dense and digitated into 5-7 points on the surface anterior to the ventral sucker, but became sparse and less digitated posteriorly toward the end of the body In adults, seven type II sensory papillae were characteristically arranged around the lip of the oral sucker, and on the inner side of the lip four small and two large type I sensory papillae were symmetrically seen on each side (12 in total). Tegumental spines on anterior two-thirds of the body. were digitated with 9-12 tips ventrally and 8-13 tips dorsally. Sperms entering into the Laurer's canal were observed. The results show that the surface ultrastructure of M. takuhashii is generally similar to those of M. yokogawai and M. miyatai except for the digitation of tegumental spines.