• Title/Summary/Keyword: Reduction methods

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Nipple Reduction with a Pentahedral Excision Technique (오면체 모양 절제법을 이용한 유두축소)

  • Hong, Yoon Gi;Sim, Hyung Bo
    • Archives of Plastic Surgery
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    • v.36 no.3
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    • pp.327-332
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    • 2009
  • Purpose: Several methods of the nipple reduction have been reported. However, the methods described previously are difficult or have some demerits. This study proposes a simple technique for reduction of the nipple height as well as diameter. Methods: The purposed nipple height is marked. A pentahedral design of excision was marked around the nipple. Local anesthetic solution was infiltrated and a 4 - 0 Nylon traction suture was applied at the nipple apex. Excision of the nipple inside both two triangles and a rectangle was made. Remaining two flaps were approximated using 5 - 0 Nylon simple interrupted sutures. However, a part of wound closure was not done in the central area of the nipple. Results: 83 patients(166 nipples) underwent this procedure from December 1999 to December 2008. Follow up ranged from 6 months to 2 years with a mean of 10 months. 78 patients were female and 5 patients were male. No major complication occurred and remaining scars were very inconspicuous. Conclusion: This simple technique has the advantage of nipple reduction in both height and diameter, and provides good aesthetic outcomes.

Active Control Methods for Drag Reduction in Flow over Bluff Bodies (뭉툭한 물체 주위 유동에서 항력 감소를 위한 능동 제어 방법)

  • Choi Haecheon
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.11-16
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    • 2002
  • In this paper, we present two successful results from active controls of flows over a circular cylinder and a sphere for drag reduction. The Reynolds number range considered for the flow over a circular cylinder is 40-3900 based on the free-stream velocity and cylinder diameter, whereas for the flow over a sphere it is $10^{5}$ based on the free-stream velocity and sphere diameter. The successful active control methods are a distributed (spatially periodic) forcing and a high-frequency (time periodic) forcing. With these control methods, the mean drag and lift fluctuations decrease and vortical structures are significantly modified. For example, the time-periodic forcing at a high frequency (larger than 20 times the vortex shedding frequency) produces $50{\%}$ drag reduction for the flow over a sphere at $Re=10^{5}$. The distributed forcing applied to the flow over a circular cylinder results in a significant drag reduction at all the Reynolds numbers investigated.

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Model Reduction Considering Both Resonances and Antiresonances (공진과 반공진 특성을 동시고려한 모델 축소)

  • 허진석;이시복;이창일
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.985-990
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    • 2001
  • The Frequency Response Function(FRF)s of FE Model reduced by SEREP methods accurately estimate the full model at resonance frequencies, However these FRFs are not accurate at antiresonance frequencies, Additionally, the truncation errors may he significant in the reduction mode1. So this paper considers the possibility of SERFP method through a numerical method to preserve dynamic behavior at antiresonance and appliers the static or dynamic compensation methods for truncation errors to the reduction model. This compensated reduction model is redesigned for pole-zero cancellation methods the objective of reducing a resonance frequency.

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Analysis of SAR Reduction Methods for Mobile Communication Handsets (이동통신단말기 SAR 저감 방안 분석)

  • 정민석;이범선
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.2
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    • pp.155-163
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    • 2002
  • In this paper, we propose SAR reduction methods based on power conservation relation, After defining SRF(SAR Reduction Factor) for a more quantitative discussion of effective SAR reduction methods, many kinds of simulation have been performed. We compare the SAR by a flip type handset with that of folder type one. It is found that in a typical position of handsets over a human head, the SAR when using the folder type is about 30 % smaller than that when using the flip type. The effects of ferrite material when using flip type handset are shown to be not considerable when using a folder type.

A DEGREE REDUCTION METHOD FOR AN EFFICIENT QUBO FORMULATION FOR THE GRAPH COLORING PROBLEM

  • Hyosang Kang;Hyunwoo Jung;Chaehwan Seol;Namho Hong;Hyunjin Lim;Seokhyun Um
    • The Pure and Applied Mathematics
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    • v.31 no.1
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    • pp.57-81
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    • 2024
  • We introduce a new degree reduction method for homogeneous symmetric polynomials on binary variables that generalizes the conventional degree reduction methods on monomials introduced by Freedman and Ishikawa. We also design an degree reduction algorithm for general polynomials on binary variables, simulated on the graph coloring problem for random graphs, and compared the results with the conventional methods. The simulated results show that our new method produces reduced quadratic polynomials that contains less variables than the reduced quadratic polynomials produced by the conventional methods.

A Study on the Method of NOx Reduction and NOx Measurement for the Diesel Engines (디젤기관의 NOx 저감방법 및 NOx 측정에 관한 연구)

  • 남정길;김준효;최주열
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2002.05a
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    • pp.193-199
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    • 2002
  • According to the NOx level requirement of annex Vl to IMO(International Maritime Organization) MARPOL 73/78, this regulation shall apply to each diesel engine with a power output of more than 130 ㎾ which is installed on a ship constructed and undergoes a major conversion on or after 1 January 2000. It is inevitable to adopt IMO standard for marine engines. Therefore, most of diesel engines which are being currently built should be tested and surveyed in accordance with the NOx technical code. In this study, various technics of NOx reduction methods were investigated for the diesel engines and the methods of NOx measuring were introduced by the new and simplified field detecting equipment. These results can be utilized for the basic design and developement of diesel engine for NOx reduction.

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Evaluation of Floor Impact Sound Performance according to the Reduction Methods (바닥충격음 저감방안에 따른 성능평가)

  • 김경우;최경석;최현중;양관섭
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.131-136
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    • 2004
  • Impact sounds, such as those created by footsteps, the dropping of an object or the moving of furniture, can be a source of great annoyance in residential buildings. The character and level of impact noise generated depends on the object striking the floor, on the basic structure of the floor, and on the floor covering. This study base on the evaluate of isolation performance of impact sound according to the impact noise reduction methods. Reduction methods consist of four ways. First way is increase thickness of bare floor and other ways are using the soft coverings on the floor and ceiling assembles. Last way is make floating floor with shock absorbing materials.

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Evaluation of Floor Impact Sound Performance according to the Reduction Methods (바닥충격음 저감방안에 따른 성능평가)

  • Choi Gyoung-Seok;Choi Hyun-jung;Yang Kwan-Seop;Kim Kyoung-Woo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.9 s.90
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    • pp.811-818
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    • 2004
  • Impact sounds, such as those created by footsteps, the dropping of an object or the moving of furniture, can be a source of great annoyance in residential buildings. The character and level of impact noise generated depends on the object striking the floor, on the basic structure of the floor, and on the floor covering. This study base on the evaluate of isolation performance of impact sound according to the impact noise reduction methods. Reduction methods consist of four ways. First way is increase thickness of bare floor and other ways are using the soft coverings on the floor and ceiling assembles. Last way is make floating floor with shock absorbing materials.

Drying methods for municipal solid waste quality improvement in the developed and developing countries: A review

  • Tun, Maw Maw;Juchelkova, Dagmar
    • Environmental Engineering Research
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    • v.24 no.4
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    • pp.529-542
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    • 2019
  • Nowadays, drying methods for municipal solid waste quality improvement have been adopted in the developed and developing countries to valorize wastes for a renewable energy source, reduce dependency on fossil fuel and keep safer disposal at landfills. Among them, biodrying, biostabilization, thermal drying and solar drying are the most common. Drying of municipal solid waste could offer several environmental and economic benefits. Therefore, this review highlighted the drying methods for municipal solid waste quality improvement around the world and compared them based on the reduction of moisture, weight and volume of municipal solid wastes against drying temperature and time by using statistical analysis. It was observed that the drying temperature of different drying methods accounted for 115 ± 40℃ for thermal drying, 59 ± 37℃ for solar drying, 55 ± 15℃ for biodrying and 58 ± 11℃ for biostabilization. Among the drying methods, thermal drying provided the shortest drying time. The moisture reduction, weight reduction, volume reduction and heating value increase of municipal solid waste could vary with drying temperature and time. Finally, the benefits and drawbacks of different drying methods were specified, and recommendations were made for the future efficient drying.

Investigation of the accuracy of different finite element model reduction techniques

  • Ghannadi, Parsa;Kourehli, Seyed Sina
    • Structural Monitoring and Maintenance
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    • v.5 no.3
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    • pp.417-428
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    • 2018
  • In this paper, various model reduction methods were assessed using a shear frame, plane and space truss structures. Each of the structures is one-dimensional, two-dimensional and three-dimensional, respectively. Three scenarios of poor, better, and the best were considered for each of the structures in which 25%, 40%, and 60% of the total degrees of freedom (DOFs) were measured in each of them, respectively. Natural frequencies of the full and reduced order structures were compared in each of the numerical examples to assess the performance of model reduction methods. Generally, it was found that system equivalent reduction expansion process (SEREP) provides full accuracy in the model reduction in all of the numerical examples and scenarios. Iterated improved reduced system (IIRS) was the second-best, providing acceptable results and lower error in higher modes in comparison to the improved reduced system (IRS) method. Although the Guyan's method has very low levels of accuracy. Structures were classified with the excitation frequency. High-frequency structures compared to low-frequency structures have been poor performance in the model reduction methods (Guyan, IRS, and IIRS).