• Title/Summary/Keyword: Process disturbances

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A Study on the Shipbuilding Yard Information System Based on Wireless LAN (Wireless LAN 기반의 조선소 현장 정보시스템에 관한 연구)

  • SEO K. H.;KIM H. M.;KIM S. Y.
    • Journal of Ocean Engineering and Technology
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    • v.19 no.6 s.67
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    • pp.86-91
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    • 2005
  • Regarding some of tire important works in tire shipyard, like tire production process, quality control, and material handling, there are many elements that disturb tire work-flaw. For example, there are mistakes in manufacturing, delay of production, and poor quality. These kinds of disturbances are from tire delay of communication time between tire production field and tire management. Therefore, it would be possible to strengthen tire competitiveness of shipbuilding industries by applying tire information technology based on Wireless Local Area Network (Wireless LAN), in order to establish tire multi-possession of real time production information in limited large shipbuilding yard. In this study, tire construction concept of tire information system, based on Wireless LAN, is proposed to build communication infrastructures in shipyards. The various information regarding shipbuilding inspection, process management, and material flaw are analyzed and constructed to databases in tire middle ware system, as tire platform for using Personal Display Agent (PDA). At last, tire middle ware system, which delivers tire information, is developed by tire C$\sharp$ and Microsoft.net; also, tire PDA application system is structured in WinCE O/S, and is tested and evaluated under tire server linked condition.

Process Performance and Bacterial Community Structure Under Increasing Influent Disturbances in a Membrane-Aerated Biofilm Reactor

  • Tian, Hailong;Yan, Yingchun;Chen, Yuewen;Wu, Xiaolei;Li, Baoan
    • Journal of Microbiology and Biotechnology
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    • v.26 no.2
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    • pp.373-384
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    • 2016
  • The membrane-aerated biofilm reactor (MABR) is a promising municipal wastewater treatment process. In this study, two cross-flow MABRs were constructed to explore the carbon and nitrogen removal performance and bacterial succession, along with changes of influent loading shock comprising flow velocity, COD, and NH4-N concentrations. Redundancy analysis revealed that the function of high flow velocity was mainly embodied in facilitating contaminants diffusion and biosorption rather than the success of overall bacterial populations (p > 0.05). In contrast, the influent NH4-N concentration contributed most to the variance of reactor efficiency and community structure (p < 0.05). Pyrosequencing results showed that Anaerolineae, and Beta- and Alphaproteobacteria were the dominant groups in biofilms for COD and NH4-N removal. Among the identified genera, Nitrosomonas and Nitrospira were the main nitrifiers, and Hyphomicrobium, Hydrogenophaga, and Rhodobacter were the key denitrifiers. Meanwhile, principal component analysis indicated that bacterial shift in MABR was probably the combination of stochastic and deterministic processes.

Recolonization of benthic macroinvertebrates after anthropogenic disturbance in natural streams, South Korea

  • Chun, Seung-Phil;Chon, Seung-Hoon;Lee, Seung-Oh;Im, Jang-Hyuk;Lee, Woo-Kyun;Kim, Myoung-Chul
    • Korean Journal of Environment and Ecology
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    • v.29 no.2
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    • pp.228-235
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    • 2015
  • Stream ecosystems are closely related to many human activities. Therefore, streams are affected by anthropogenic disturbances such as riverine development and gravel-mining as well as deterioration of water quality. The goal of this study was to elucidate the recolonization process of the macroinvertebrate community after a small-scale anthropogenic disturbance. Field studies were conducted at three sites in a natural stream. The number of recolonizing species tended to increase slightly over time, exceeding the total species number of the control. Ephemeroptera contributed the most to shaping the recolonizing pattern of the entire community. From the result of changes in dominant species, the early recolonizers of each site were the species that showed more frequent occurrence particulary at each sites. But the late recolonizers are Chironomidae at all the sites commonly. This result implies that the actual differences exist among the recolonizing trends of each benthic macroinvertebrate taxon. Collector-gatherers and scrapers comprised about 70% of the recolonizing species. These results indicate that the recolonizing process of an aquatic community after an artificial disturbance depends on the environmental conditions(particularly substratum composition or organic pollution) of the habitat.

Using Ambient Control to Prevent External Disturbances in Large-scale Furnace (대형 용해로의 외부 환경변수를 통제하기 위한 주변 환경관리의 활용)

  • Cho, Jin-Hyung;Chang, Sung-Ho;Lee, Sae-Jae;Jang, Do-Soo;Suh, Jung-Yul;Oh, Hyun-Seung
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.29 no.2
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    • pp.92-96
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    • 2006
  • Large glass furnaces to produce glass for CRT are housed in huge chambers. It is costly to maintain such a chamber in constant temperature, humidity, and(air) pressure. In this study, first, we show that the process of such a huge furnace, which requires the steady maintenance of high temperature, is badly affected by the ambient temperature of surrounding air. Second, an alternative process which not only maintains the relatively constant temperature dispersion around the furnace, but is also economical will be proposed. We calculate the necessary volume of air inflow in the appendix.

Real-time Reflection Light Detection Algorithm using Pixel Clustering Data (Pixel 군집화 Data를 이용한 실시간 반사광 검출 알고리즘)

  • Hwang, Dokyung;An, Jongwoo;Kang, Hosun;Lee, Jangmyung
    • The Journal of Korea Robotics Society
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    • v.14 no.4
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    • pp.301-310
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    • 2019
  • A new algorithm has been propose to detect the reflected light region as disturbances in a real-time vision system. There have been several attempts to detect existing reflected light region. The conventional mathematical approach requires a lot of complex processes so that it is not suitable for a real-time vision system. On the other hand, when a simple detection process has been applied, the reflected light region can not be detected accurately. Therefore, in order to detect reflected light region for a real-time vision system, the detection process requires a new algorithm that is as simple and accurate as possible. In order to extract the reflected light, the proposed algorithm has been adopted several filter equations and clustering processes in the HSI (Hue Saturation Intensity) color space. Also the proposed algorithm used the pre-defined reflected light data generated through the clustering processes to make the algorithm simple. To demonstrate the effectiveness of the proposed algorithm, several images with the reflected region have been used and the reflected regions are detected successfully.

Fabrication of Phase Plate to Simulate Turbulence Effects on an Optical Imaging System in Strong Atmospheric Conditions

  • Han-Gyol Oh;Pilseong Kang;Jaehyun Lee;Hyug-Gyo Rhee;Young-Sik Ghim;Jun Ho Lee
    • Current Optics and Photonics
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    • v.8 no.3
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    • pp.259-269
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    • 2024
  • Optical imaging systems that operate through atmospheric pathways often suffer from image degradation, mainly caused by the distortion of light waves due to turbulence in the atmosphere. Adaptive optics technology can be used to correct the image distortion caused by atmospheric disturbances. However, there are challenges in conducting experiments with strong atmospheric conditions. An optical phase plate (OPP) is a device that can simulate real atmospheric conditions in a lab setting. We suggest a novel two-step process to fabricate an OPP capable of simulating the effects of atmospheric turbulence. The proposed fabrication method simplifies the process by eliminating additional activities such as phase-screen design and phase simulation. This enables an efficient and economical fabrication of the OPP. We conducted our analysis using the statistical fluctuations of the refractive index and applied modal expansion using Kolmogorov's theory. The experiment aims to fabricate an OPP with parameters D/r0 ≈ 30 and r0 ≈ 5 cm. The objective is defined with the strong atmospheric conditions. Finally, we have fabricated an OPP that satisfied the desired objectives. The OPP closely simulate turbulence to real atmospheric conditions.

A Study on Real Time Working Path Control of Vertical Articulated Robot for Forging Process Automation in High Temperature Environments (고온 환경 단조공정 자동화를 위한 수직다관절 로봇의 실시간 작업경로 제어에 관한 연구)

  • Jo, Sang-Young;Kim, Min-Seong;Do, Ki-Hoon;Han, Sung-Hyun;Ha, Un-Tae;Shim, Hyun-Suk;Lim, Chang-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.20 no.1
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    • pp.34-48
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    • 2017
  • This study proposes a new approach to control a trajectory control of vertical type articulated robot arm with six revolution joints by computed torque method for manufacturing process automation. The proposed control scheme takes advantage of the properties of the fuzzy controllers. The proposed method is suitable to control of the trajectory and path control in cartesian space for vertical type articulated robot manipulator for forging manufacturing process automation. The results is illustrated that the proposed fuzzy computed torque controller is more stable and robust than the conventional computed torque controller. This study is included with an analytical methodology of inverse kinematic computation for 6 DOF manipulators. And an intelligent PID based on feed forward fuzzy control structure is applied to control the working path control with disturbances caused by uncertainty parameters of the manipulator dynamic model. Lastly, the validity of proposed is verified by simulations and experiments.

Incidence of pterygospinous and pterygoalar bridges in dried skulls of Koreans

  • Ryu, Sol-Ji;Park, Min-Kyu;Lee, U-Young;Kwak, Hyun-Ho
    • Anatomy and Cell Biology
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    • v.49 no.2
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    • pp.143-150
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    • 2016
  • Understanding of morphological structures such as the sphenoid spine and pterygoid processes is important during lateral transzygomatic infratemporal fossa approach. In addition, osseous variations such as pterygospinous and pterygoalar bridges are significant in clinical practice because they can produce various neurological disturbances or block the passage of a needle into the trigeminal ganglion through the foramen ovale. Two hundred and eighty-four sides of Korean adult dry skulls were observed to carry out morphometric analysis of the lateral plate of the pterygoid process, to investigate, for the first time among Koreans, the incidence of the pterygospinous and pterygoalar bony bridges, to compare the results with those available for other regional populations, and to discuss their clinical relevance as described on literatures. The mean of maximum widths of the left and right lateral plates of the pterygoid process were 15.99 mm and 16.27 mm, respectively. Also, the mean of maximum heights of the left and right lateral plates were 31.02 mm and 31.01 mm, respectively. The ossified pterygospinous ligament was observed in 51 sides of the skulls (28.0%). Ossification of the pterygospinous ligament was complete in four sides (1.4%). In 47 sides (16.6%), the pterygospinous bridge was incomplete. The ossified pterygoalar ligament was observed in 24 sides of the skulls (8.4%). Ossification was complete in eight sides (2.8%) and incomplete in 16 sides (5.6%). This detailed analysis of the lateral plate of the pterygoid process and related ossification of ligaments can improve the understanding of complex clinical neuralgias associated with this region.

Development of Strain-gauge-type Rotational Tool Dynamometer and Verification of 3-axis Static Load (스트레인게이지 타입 회전형 공구동력계 개발과 3축 정적 하중 검증)

  • Lee, Dong-Seop;Kim, In-Su;Lee, Se-Han;Wang, Duck-Hyun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.9
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    • pp.72-80
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    • 2019
  • In this task, the tool dynamometer design and manufacture, and the Ansys S/W structural analysis program for tool attachment that satisfies the cutting force measurement requirements of the tool dynamometer system are used to determine the cutting force generated by metal cutting using 3-axis static structural analysis and the LabVIEW system. The cutting power in a cutting process using a milling tool for processing metals provides useful information for understanding the processing, optimization, tool status monitoring, and tool design. Thus, various methods of measuring cutting power have been proposed. The device consists of a strain-gauge-based sensor fitted to a new design force sensing element, which is then placed in a force reduction. The force-sensing element is designed as a symmetrical cross beam with four arms of a rectangular parallel line. Furthermore, data duplication is eliminated by the appropriate setting the strain gauge attachment position and the construction of a suitable Wheatstone full-bridge circuit. This device is intended for use with rotating spindles such as milling tools. Verification and machining tests were performed to determine the static and dynamic characteristics of the tool dynamometer. The verification tests were performed by analyzing the difference between strain data measured by weight and that derived by theoretical calculations. Processing test was performed by attaching a tool dynamometer to the MCT to analyze data generated by the measuring equipment during machining. To maintain high productivity and precision, the system monitors and suppresses process disturbances such as chatter vibration, imbalances, overload, collision, forced vibration due to tool failure, and excessive tool wear; additionally, a tool dynamometer with a high signal-to-noise ratio is provided.

An Inquiry into the Taboo of the Burial Shroud (수의의 금기에 관한 고찰)

  • 남민이
    • The Research Journal of the Costume Culture
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    • v.7 no.3
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    • pp.50-57
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    • 1999
  • Folk belief, which originated with the rise of human existence is a fundamental and comprehensive mode of living that reflects sociocultural conditions. Adherents of folk belief accept a certain thing to be true and real without scientific authority and absolute certainty. Taboo can be seen as a king of folk belief. The object of this study is to examine the taboos in relation to the manufacturing process and the quality of the shroud and to shrouding customs. I will also try to find out the meaning and significance in this. Through this task, I hope to contribute to the enhanced understanding of the cultural characteristics, the spiritual life, and the views on after life of the Korean people. In Korea, it is considered to be propitious to prepare the shroud on the intercalary month of the leap year , as it allows one to enjoy longevity healthy and sound. Moreover, as this belief gives credence and repose while preparing for the “final departure”, this custom is relatively well observed. From the taboo concerning leap months, we infer that death as viewed as a commencement of a new life, which reveals a positive view on afterlife. This can be seen as a return to the origin of anti-universal space in this “bonus” month of anti-universal time. Taboos on the manufacturing process of the shroud is related to the belief that it allows the deceased to go the nest world without any hesistation or disturbances. This symbolizes the immortality of the human soul: I. e. that the human spirit does not end in this world but continues on to the next. Taboos concerning the preparation process of the shroud as well as various other taboos are related to the belief that preparation for the shroud should be done in sincerity and secredness with a thoughtful consideration for the deceased. This can be perceived as an implication to sanctity for the dead.

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