• Title/Summary/Keyword: Simplex

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Motion-Vector Refinement for Video Error Concealment Using Downhill Simplex Approach

  • Kim, Do-Hyun;Kwon, Young-Jin;Choi, Kyoung-Ho
    • ETRI Journal
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    • v.40 no.2
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    • pp.266-274
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    • 2018
  • In error-prone wireless environments, it is difficult to realize video coding systems that are robust to various types of data loss. In this paper, a novel motion-vector refinement approach is presented for video error concealment. A traditional boundary-matching approach is exploited to reduce blocky effects along the block boundary. More specifically, a downhill simplex approach is combined with a boundary-matching approach to fine-tune the motion vectors, reducing the blocky effects along the prediction unit block boundary, and minimizing the computational cost. Extensive simulations are performed, and the results obtained verify the robustness and effectiveness of the proposed approach.

Findings of $^{99m}TC-HMPAO$ Regional Cerebral Blood Flow SPECT in a Case of Herpes Simplex Encephalitis (단순포진 뇌염의 $^{99m}TC-HMPAO$ 국소 뇌혈류 SPECT의 소견)

  • Ahn, Myeong-Im;Lee, Sung-Yong;Kim, Jong-Woo;Bahk, Yong-Whee
    • The Korean Journal of Nuclear Medicine
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    • v.23 no.1
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    • pp.85-87
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    • 1989
  • Herpes simplex encephalitis (HSE) is one of the fulminant necrotizing, often fatal sporadic form of the encephalitis caused by herpes simplex type I virus. Characteristically, there is early and almost constant involvement of one or both temporal lobes, although there are common additional areas of involvement. Appropriate early treatment following correct diagnosis by clinical findings, CSF study, EEG and several radiological studies including angiography, redionuclide studies, CT or MRI can reduce its mortality and severity of the sequelae. We report a case of HSE diagnosed by adjuvant study of $^{99m}Tc-HMPAO$ regional cerebral blood flow SPECT, which showed a marked increase in bitemporal cerebral blood flow in a 24-year-old man.

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An Enhanced Genetic Algorithm for Global and Local Optimization Search (전역 및 국소 최적화탐색을 위한 향상된 유전 알고리듬의 제안)

  • Kim, Young-Chan;Yang, Bo-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.6
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    • pp.1008-1015
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    • 2002
  • This paper proposes a combinatorial method to compute the global and local solutions of optimization problem. The present hybrid algorithm is the synthesis of a genetic algorithm and a local concentrate search algorithm (simplex method). The hybrid algorithm is not only faster than the standard genetic algorithm, but also gives a more accurate solution. In addition, this algorithm can find both the global and local optimum solutions. An optimization result is presented to demonstrate that the proposed approach successfully focuses on the advantages of global and local searches. Three numerical examples are also presented in this paper to compare with conventional methods.

A Case of Postoperative Herpes Simplex Pneumonia

  • Lee, Tae-One;Hwang, Hyung-Sik;Moon, Seung-Myung;Choi, Sun-Kil
    • Journal of Korean Neurosurgical Society
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    • v.41 no.3
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    • pp.204-206
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    • 2007
  • Herpes simplex virus [HSV] esophagitis is a rare disease and most of cases are reported in the immunocompromised patients. We report a case of fatal HSV infection started from herpes labialis and esophagitis. She had initially suffered from perioral ulcer, esophagitis, and interstitial pneumonitis later and eventually died of respiratory insufficiency one month later after the aneurysmal surgery. She did not have any immunocompromised medical history and also had no evidence of herpes encephalitis in laboratory study and magnetic resonance image [MRI]. With the availability of effective agents for the treatment of HSV infection, early recognition of HSV esophagitis is important because it may be clinically confused with Cushing ulcer and may be complicated with a fatal pneumonitis.

Glioblastoma Mimicking Herpes Simplex Encephalitis

  • Nam, Tai-Seung;Choi, Kang-Ho;Kim, Myeong-Kyu;Cho, Ki-Hyun
    • Journal of Korean Neurosurgical Society
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    • v.50 no.2
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    • pp.119-122
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    • 2011
  • We report a case of 70-year-old man with glioblastoma presenting as acute encephalitic illness. The patient exhibited sudden onset of cognitive impairment and headache for 2 days. Initial brain MRI showed left temporal lobe hyperintensity, and cerebrospinal fluid cytology revealed a mild pleocytosis. The patient had initially improved after medical treatment with a presumptive diagnosis of herpes simplex encephalitis (HSE). After 8 months, the patient complained of recurrent seizures. A follow-up brain MRI revealed marked increases in size and surrounding perilesional edema in the left temporal lesion on T2-weighted images and a new contrast-enhancing lesion on gadolinium-enhanced T1-weighted images. Stereotactic brain biopsy revealed a glioblastoma. The atypical encephalitic presentation of glioblastoma should be considered if definitive evidence for the diagnosis of HSE cannot be obtained.

Development of LPAKO : Software of Simplex Method for Liner Programming (단체법 프로그램 LPAKO 개발에 관한 연구)

  • 박순달;김우제;박찬규;임성묵
    • Korean Management Science Review
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    • v.15 no.1
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    • pp.49-62
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    • 1998
  • The purpose of this paper is to develope a large-scale simplex method program LPAKO. Various up-to-date techniques are argued and implemented. In LPAKO, basis matrices are stored in a LU factorized form, and Reid's method is used to update LU maintaining high sparsity and numerical stability, and further Markowitz's ordering is used in factorizing a basis matrix into a sparse LU form. As the data structures of basis matrix, Gustavson's data structure and row-column linked list structure are considered. The various criteria for reinversion are also discussed. The dynamic steepest-edge simplex algorithm is used for selection of an entering variable, and a new variation of the MINOS' perturbation technique is suggested for the resolution of degeneracy. Many preprocessing and scaling techniques are implemented. In addition, a new, effective initial basis construction method are suggested, and the criteria for optimality and infeasibility are suggested respectively. Finally, LPAKO is compared with MINOS by test results.

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Real-time Flood Forecasting Model for Irrigation Reservoir Using Simplex Method (최적화기법에 의한 관개저수지의 실시간 홍수예측모형)

  • 문종필;김태철
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.43 no.2
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    • pp.85-93
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    • 2001
  • The basic concept of the model is to minimize the error range between forecasted flood inflow and actual flood inflow, and forecast accurately the flood discharge some hours in advance depending on the concentration time(Tc) and soil moisture retention storage(Sa). Simplex method that is a multi-level optimization technique was used to search for the determination of the best parameters of RETFLO (REal-Time FLOod forecasting) model. The flood forecasting model developed was applied to several strom event of Yedang reservoir during past 10 years. Model perfomance was very good with relative errors of 10% for comparison of total runoff volume and with one hour delayed peak time.

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Design optimization of spot welded structures to attain maximum strength

  • Ertas, Ahmet H.
    • Steel and Composite Structures
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    • v.19 no.4
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    • pp.995-1009
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    • 2015
  • This study presents design optimization of spot welded structures to attain maximum strength by using the Nelder-Mead (Simplex) method. It is the main idea of the algorithm that the simulation run is executed several times to satisfy predefined convergence criteria and every run uses the starting points of the previous configurations. The material and size of the sheet plates are the pre-assigned parameters which do not change in the optimization cycle. Locations of the spot welds, on the other hand, are chosen to be design variables. In order to calculate the objective function, which is the maximum equivalent stress, ANSYS, general purpose finite element analysis software, is used. To obtain global optimum locations of spot welds a methodology is proposed by modifying the Nelder-Mead (Simplex) method. The procedure is applied to a number of representative problems to demonstrate the validity and effectiveness of the proposed method. It is shown that it is possible to obtain the global optimum values without stacking local minimum ones by using proposed methodology.

A New 5α, 8α-Epidioxy Sterol from the Marine Sponge Plakortis simplex

  • Oh, Jung-Soon;Kim, Myoung-Ha;Song, Ah-Rin;Rho, Jung-Rae
    • Journal of the Korean Magnetic Resonance Society
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    • v.14 no.1
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    • pp.1-8
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    • 2010
  • Four 5,8-epidioxy sterols were isolated from the marine sponge Plakortis simplex. Their structures were completely determined by an extensive NMR analysis and comparison with NMR data of similar compounds for absolute stereochemistry of the side chain. The compounds were assigned as 5,8-epidioxy- (24S)-ethylcholesta-6,22(E),25-trien-3-ol(1), 5,8-epidioxy-(24S)-methylcholesta- 6,22(E)-dien-3-ol(2), 5,8-epidioxycholesta-6,22(E)-dien-3-ol(3) and 5,8- epidioxycholesta-6-en-3-ol (4).

Four new cyclic peroxides from the Marine Sponge Plakortis simplex

  • Hwang, Buyng Su;Rho, Jung-Rae
    • Journal of the Korean Magnetic Resonance Society
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    • v.17 no.1
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    • pp.47-53
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    • 2013
  • Four new cyclic peroxide compounds (1~4) were isolated from the marine sponge Plakortis simplex. Their structures including relative stereochemistry were determined by MS and NMR analysis. All compounds, a side carbon chain with 10 carbons, were very unstable. After transformation into methyl ester analogues, the structure determination was conducted. Compounds 1a and 2a are stereoisomers, assigned as $3S^*$, $4S^*$, $6R^*$ and $3R^*$, $4S^*$, $6R^*$, respectively. Similarly, compounds 3a and 4a, replaced the methoxy group with an aliphatic methyl, are also stereoisomers. Compounds 1a and 2a exhibited the strong antifungal effect against the fungus Candida albicans.