• Title/Summary/Keyword: Ball-based

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Strategies for Developing the Coastal Community-Based Resort Activating the Community Economy - Focused on the East Coastal Community in Kangwon-do - (지역경제 활성화를 위한 해안마을단위 리조트 개발방향 -강원 동해안 해안마을을 중심으로-)

  • Kim, Sam-neung
    • Journal of the Korean Institute of Rural Architecture
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    • v.5 no.3
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    • pp.8-21
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    • 2003
  • The purpose of this study was to work out the strategies for developing the east coastal community-base resort activating the community economy. The results of this study were as follows; presented village unit resort development that secure unique community activity to seashore village inhabitants and offer natural rest space and recreation space to user for the idealest development direction. And presented space composition direction so that can develop nature rest ball such as nature walk road that introduce concept of "The street" in this resort development. Also, through belt style development, proposed resources between the seashore village that must share reciprocity.

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GMM-Based Maghreb Dialect Identification System

  • Nour-Eddine, Lachachi;Abdelkader, Adla
    • Journal of Information Processing Systems
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    • v.11 no.1
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    • pp.22-38
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    • 2015
  • While Modern Standard Arabic is the formal spoken and written language of the Arab world; dialects are the major communication mode for everyday life. Therefore, identifying a speaker's dialect is critical in the Arabic-speaking world for speech processing tasks, such as automatic speech recognition or identification. In this paper, we examine two approaches that reduce the Universal Background Model (UBM) in the automatic dialect identification system across the five following Arabic Maghreb dialects: Moroccan, Tunisian, and 3 dialects of the western (Oranian), central (Algiersian), and eastern (Constantinian) regions of Algeria. We applied our approaches to the Maghreb dialect detection domain that contains a collection of 10-second utterances and we compared the performance precision gained against the dialect samples from a baseline GMM-UBM system and the ones from our own improved GMM-UBM system that uses a Reduced UBM algorithm. Our experiments show that our approaches significantly improve identification performance over purely acoustic features with an identification rate of 80.49%.

The Wear Mechanism of Carbon(WC/C) Thin Film in Lubricated Contact (WC/C 박막의 윤활접촉하의 마멸기구)

  • Ahn, Hyo-Sok;Kim, Doo-In
    • Tribology and Lubricants
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    • v.24 no.6
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    • pp.302-307
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    • 2008
  • The running-in behaviour of the metal carbon coating (WC/C) was evaluated with regard to its applicability as wear-resistant coating for key components in engines. Reciprocating wear tests under lubricated condition employing an oscillating friction wear tester were performed to investigate the tribological behaviors of the coatings in ambient environment. Confocal microscopy and scanning electron microscopy were used to observe worn surfaces and the wear scars on the steel balls. Elemental composition of the coating and worn surfaces were characterized using Auger electron spectroscopy. The friction behavior of WC/C coating was comparable to common carbon-based coatings. Thin tribofilm was formed on the worn surface of the steel ball due to material transfer and tribochemical reaction whereas there was no evidence of tribofilm generation on the coating surface. indicating the chemical innertness of WC/C coating.

Contouring Tool Path Generation for Dieless CNC Forming using STL Offset (STL offset을 이용한 다이레스 CNC 포밍용 등고선 공구경로 생성)

  • Kang Jae-Gwan;Choi Dong-Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.2 s.179
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    • pp.191-198
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    • 2006
  • Dieless CNC forming is an innovative technology which can form various materials with complex shape by numerically controlled incremental forming process. In this paper, a method of NC tool path generation based on an STL file for dieless CNC forming is proposed. Tool trajectory adopts the principle of layered manufacturing in rapid prototyping technology, but it is necessary to consider STL offset because of the ball shaped tool with a radius. Vertex offset method which enables to compute offset STL directly is engaged for STL offset. The offseted STL is sliced by cutting planes to generate contouring tool path. Algorithm is implemented on a computer and experimented on a dieless CNC forming machine to show its validity.

A study on the surface roughness assessment of polished surfaces (연마 다듬질 가공면의 표면 미세형상 평가에 관한 연구)

  • 조남규;김현국;권기환;한창수;안유민;이성환;박균명
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.326-331
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    • 2000
  • This paper describes the statistical analysis techniques for the surface roughness assessment of polished surfaces. In experiments, the polishing process of the sample surfaces which are manufactured by ball end mill is consist of two steps; the cusp removal process and the surface finishing process. For the cusp removal process, the criterion of cusp removal was established from the power spectrum analysis to assess the change of the cusp removal rate. For the finishing process, the surface was polished by the rotational CBN tool and vibration wood tool. And the surface quality of polished surface was assessed using the functional parameters based on the statistical values of surface profiles. Consequently, the surface finish performance of the polished surface using the vibration wood tool was improved.

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Analysis of Nano-contact Between Nano-asperities Using Atomic Force Microscopy (나노스케일 표면돌기 간의 미세접촉에 대한 해석)

  • Ahn, Hyo-Sok;Jang, Dong-Young
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.18 no.4
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    • pp.369-374
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    • 2009
  • In micro/nano-scale contacts in MEMS and NEMS, capillary and van der Waals forces generated around contacting micro-asperities significantly influence the performance of concerning device as they are closely related to adhesion and stiction of interacting surfaces. In this regard, it is of prime importance to accurately estimate the magnitude of surface forces so that an optimal solution for reducing friction and adhesion of micro/nano-surfaces may be obtained We introduced an effective method to calculate these surface forces based on topography information obtained from an atomic force microscope. This method was used to calculate surface forces generated in the contact interface formed between diamond-like carbon coating and $Si_3N_4$ ball. This method is shown to effectively demonstrate the influence of capillary force in the contact area, especially in humid atmosphere.

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A Study on the Rotordynamic Stability of Turbo Pump Unit

  • Kwak, Hyun-Duck;Lee, Yong-Bok;Kim, Chang-Ho;Ha, Tae-Woong;Yoo, Woo-Chul
    • KSTLE International Journal
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    • v.4 no.1
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    • pp.1-7
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    • 2003
  • A turbo pump unit provides high pressure oxygen and fuel in a space shuttle main engine (SSME). This paper focused on rotordynamics, investigating its characteristics based on a numerical simulation of turbo pump finite element model. Speeds up to 50,000 rpm are considered, as well as the special problems related to elastic-ring, seal hydrodynamic force, shroud force and clearance-excitation farce. The rotordynamic prediction shows that the elastic-ring which is inserted between the casing and the outer race of ball bearing allows far an acceptable separate margin of first critical speed. Additionally, the results show that the floating ring seal, which have a peculiar ring, adds substantial stiffness and damping to the system as well as exhibits superior performance in terms of rotordynamic stability of system compared to the plain seal.

Floor impact sound classification and setting Acceptable limit based on psychoacoustical evaluation (감성평가 기반 바닥충격음 등급화 및 수인한도 설정)

  • Kim, Sung Min;Hong, Joo Young;Jeon, Jin Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.7-9
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    • 2014
  • An auditory experiment was conducted to establish annoyance criteria for floor impact noise in apartment buildings. Heavyweight floor impact sounds were recorded using an impact ball; the impact sound pressure level (SPL) together with the temporal decay rate (DR), which is quantified by the dB drop per second, was analyzed. For the experiment, A-weighted exposure levels of the heavy-weight floor impact sounds ranging 34~73 dB were evaluated at 3 dB intervals. Participants used a 7-point verbal scale to evaluate the level of annoyance from floor impact noise. The results show that the annoyance increases with increasing impact SPL and decreasing DR. Consequently, a classification and an acceptable level of floor impact sounds were proposed.

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Computer Aided Process Design in Cold-Former Forging (컴퓨터를 이용한 냉간포머단조 공정설계)

  • 임창수;서성렬;이민철;김주현;전만수
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.10
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    • pp.51-57
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    • 1998
  • In this paper, a computer aided process design technique, utilizing a forging simulator and a commercial CAD software, is presented together with its related design system for cold-former forging of ball joints. The forging sequence design is carried out through user-computer interaction by using design templates, design database, experience or knowledge-based rules and some basic laws found in the literature. The forging simulation technique is used to verify the process design. The detail designs including die set drawings and die manufacturing information are automatically generated. It has been shown that the engineer ing and design productivity is much improved by the presented approach in the practical standpoint of process design engineers.

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Prediction of Density Distribution in Sintered Metal Powder Compacts by Indentation Force Equation (압흔하중식에 의한 금속소결분말체내에서의 밀도분포 예측)

  • 박종진
    • Journal of Powder Materials
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    • v.4 no.3
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    • pp.188-195
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    • 1997
  • In most of sintered metal powder compacts, the sintered density distribution is controlled to be as high and uniform as possible to ensure the required mechanical properties. In general, the density distribution in the compacts is not uniform and not easy to measure. In the present study, a method for measuring the density distribution was developed, based on the indentation force equation by which the hardness and the relative density were related. The indentation force equation, expressed as a function of strength constant, workhardening coefficient and relative density, was obtained by finite element analysis of rigid-ball indentation on sintered powder metal compacts. The present method was verified by comparing the predicted density distribution in the sintered Fe-0.5%C-2%Cu compacts with that obtained by experiments, in which the density distribution was directly measured by machining the compacts from the outer surface progressively.

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