• Title/Summary/Keyword: slippery

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A Study on the Allowances of Aircraft Landing Distance (항공기 착륙거리의 여유분 산정에 관한 연구)

  • Noh, Kun-Soo;Kim, Woong-Yi
    • Journal of Advanced Navigation Technology
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    • v.17 no.3
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    • pp.279-284
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    • 2013
  • Among the phases of flight operations pilots feel much pressure in landing segment. There is a number of factors affecting landing safety while pilots reduce aircraft speeds and make a touchdown and stop completely. If runway length is sufficient for landing, there maybe is no problem. But it is not the case all the time. So it is necessary to confirm whether landing performance is within limits or not. Required landing distance is actual landing distance demonstrated by flight test pilot plus allowances for average airline pilots. FAR(Federal Aviation Regulations) AFM certification is based upon manual landing for dry and wet runway. Other runway conditions are not the certification basis. JAR dictates even contaminated/slippery runway is included by prescribed allowances. Automatic landing is not certification basis, so actual landing distances are provided. In this paper I would like to analyze distance allowances included in each type of runway condition. In addition there is no regulation about allowances for specific runway condition, I would suggest adequate allowances for that case.

Operating status of Korean coastal composite fishing boats by the questionnaire survey (설문조사를 통한 우리나라 연안복합어선의 조업 실태)

  • HWANG, Bo-Kyu;CHANG, Ho-Young;KIM, Min-Son
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.54 no.4
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    • pp.324-332
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    • 2018
  • We conducted a questionnaire survey to analyze the current status of the coastal composite fisheries, as well as the improvement point in designing a new type coastal composite fishing boat suitable for Korean fishing environments from April to August 2017. The questionnaire composed of 20 questions about the features of the coastal composite fishing boat and fishing work. The survey sites were selected to cover all parts of the country by considering the geographical position. The significance testing for the response results was accessed by ${\chi}^2$ test and ANOVA. The results revealed that more than half (59.1%) of the fishermen operated one day per voyage and operating alone topped with 22.5% in the number of crews, followed by 2 persons (20.3%) and 5 persons (22.1%). The navigation devices had a high rate of installation and GPS plotter ranked first in the devices. In addition, fish finder ranked first in fishing equipment, followed by net hauler. The most inconvenient work that they felt during the fishing operation was fish handing at 49.8% and other general fishing works like setting and hauling line, deck cleaning accounted for about 25%. The hardest work was the accident by ropes wrapped around propeller and the engine trouble came in second. The most inconvenient facilities to the present design of fishing boat was wheelhouse (76.7%), followed by fish hold (38.5%), and deck (35.1%). Furthermore, inconvenient points related to the movement of fishing gear, noise and vibration of engine, slippery deck and small fish hold exceeded 50%.

Long-Haul Truck Driver Training Does Not Meet Driver Needs in Canada

  • Malkin, Jennifer;Crizzle, Alexander M.;Zello, Gordon;Bigelow, Philip;Shubair, Mamdouh
    • Safety and Health at Work
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    • v.12 no.1
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    • pp.35-41
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    • 2021
  • Introduction: Training standards for long-haul truck drivers (LHTD) are rapidly evolving in Canada, yet the opinions of the drivers themselves have not been adequately considered. The purpose was to survey LHTD on their work training history and to examine LHTD perceptions of driver training and licensing protocols. Methods: LHTD were recruited across two Western Canadian provinces from seven different truck stops. The sample completed 207 surveys and 67 semi-structured interviews. Results: The average age of the participants was 52.5 ± 11.5 years (range 24-79); 96% were men. Approximately 33% of the LHTD had at least one crash. Those who did not receive formal driver training were significantly more likely to crash than those who had received training. Participants stated that current training standards are inadequate for the industry, particularly for new drivers. According to participants, entry-level curriculums should consist of both classroom and practical training, as well as on-road observation with a senior mentor. LHTD reported that many new drivers are not equipped to drive in various contexts and settings (e.g., mountains, slippery roads). Conclusions: LHTD are not confident in the current training guidelines for novice truck drivers. Revisions to the training curriculum and standardization across Canada should be considered. Practical Application: A federal mandatory entry-level training program is needed in Canada to ensure that all new LHTD ascertain the necessary skills to drive safely. Such a program requires government involvement and input from LHTD to facilitate appropriate licensure and consistent training for all drivers.

A Study on Comparative Pulse Diagnosis of Renying Pulse(人迎脈) and Cunkou Pulse(寸口脈) (인영촌구비교맥진(人迎寸口比較脈診)에 관한 연구)

  • Yun, Chang-Yeol
    • Journal of Korean Medical classics
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    • v.32 no.4
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    • pp.35-46
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    • 2019
  • Objectives : While Comparative Pulse Diagnosis of Renying pulse(人迎脈) and Cunkou pulse(寸口脈) is one of the three major pulse diagnostic methods in "Huangdineijing" along with Three Positions and Nine Indicators Pulse Diagnosis(三部九候脈診法) and Cunkou Pulse Diagnosis(寸口脈診法), it has died out in later periods. This study aims to examine this lost method. Methods : Annotations of "Huangdineijing" were examined along with descriptions of the author's own experience. Results & Conclusions : Renying is the Renying(人迎) point from the Stomach Channel(ST), while Cunkou is the Taiyuan(太淵) point from the Lung Channel(LU). These two points are compared in order to determine the deficiency and excess of the Zangfu(臟腑). Normal pulses(平脈) are Soft(軟脈) or Moderate(緩脈), while Stirred pulses(躁脈) are Stringy(弦脈), Tight(緊脈), Slippery(滑脈) or Long(長脈). If the Renying is once active where Shaoyang pulse is active, purge the Gallbladder and supplement the Liver. If there is Stirred pulse, purge the Triple Burner and supplement the Pericardium. If the Renying is twice active where Taiyang pulse is active, purge the Bladder and supplement the Kidney. If there is Stirred pulse, purge the Small Intestine and supplement the Heart. If the Renying is three times active, where Yangming pulse is active, purge the Stomach and supplement the Spleen. If there is Stirred pulse, purge the Large Intestine and supplement the Lung. If the Cunkou is once active where the Jueyin pulse is active, purge the Liver and supplement the Gallbladder. If there is Stirred pulse, purge the Pericardium and supplement the Triple Energizer. If the Cunkou is twice active where the Shaoyin pulse is active, purge the Kidney and supplement the Bladder. If there is stirred pulse, purge the Heart and supplement the Small Intestine. If the Cunkou is three times active where the Taiyin pulse is active, purge the Stomach and supplement the Spleen. If there is Stirred pulse, purge the Lung and supplement the Large Intestine.

A Study on User Evaluation about Package Design of Home Meal Replacement (가정편의식 패키지 디자인에 대한 사용자 평가 연구)

  • Yang, Keunyoung
    • Design Convergence Study
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    • v.18 no.1
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    • pp.49-60
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    • 2019
  • While one person household and nuclear family have been increasing, supermarkets began to launch home meal replacement(HMR) promotion. Each brand competes over various types of HMR such as box lunch. In particular, the sales of HMR have been increasing due to one-person households. Experts predicted HMR market will be increased in the future as well. This study presents design evaluation with regards to HMR package design for elders. The methods of this study are: First, research literature review on senior society and analyse the design for both domestic and foreign HMR products. Second, survey on product design for evaluation was conducted. Third, user's evaluation survey was conducted on elders. As a result, containers mostly came in cup or box shaped package designs. The package provided both still and illustration image of food. The HMR design for elders are recommended as follows: first, HMR should be service designed for users. Second, the design should be for elders as well. Third, the design should be empathetic and abundant. For user-interface, the packaging material shall not be slippery and the shape of grip should be considered thoroughly for the elder's design.

Geometrical Design and SLIPS Lubrication for Enhancement of Negative-pressure-driven Internal Flow Rate in Metal Pipes (금속관 내부의 음압유량 향상을 위한 기하학적 디자인 및 SLIPS 윤활)

  • Kim, Dong Geun;Jang, Changhwan;Kim, Seong Jae;Kim, Daegyoum;Kim, Sanha
    • Tribology and Lubricants
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    • v.37 no.6
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    • pp.253-260
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    • 2021
  • Metal pipes are used in a wide range of applications, from plumbing systems of large construction sites to small devices such as medical tools. When a liquid is enforced to flow through a metal pipe, a higher flow rate is beneficial for higher efficiency. Using high pressures can enhance the flow rate yet can be harmful for medical applications. Thus, we consider an optimal geometrical design to increase the flow rate in medical devices. In this study, we focus on cannulas, which are widely used small metal pipes for surgical procedures, such as liposuction. We characterize the internal flow rate driven by a negative pressure and explore its dependence on the key design parameters. We quantitatively analyze the suction characteristics for each design variable by conducting computational fluid dynamics simulations. In addition, we build a suction performance measurement system which enables the translational motion of cannulas with pre-programmed velocity for experimental validation. The inner diameter, section geometry, and hole configuration are the design factors to be evaluated. The effect of the inner diameter dominates over that of section geometry and hole configuration. In addition, the circular tube shape provides the maximum flow rate among the elliptical geometries. Once the flow rate exceeds a critical value, the rate becomes independent of the number and width of the suction holes. Finally, we introduce a slippery liquid-infused nanoporous surface (SLIPS) coating using nanoparticles and hydrophobic lubricants that effectively improves the flow rate and antifouling property of cannulas without altering the geometrical design parameter.

Landslide risk zoning using support vector machine algorithm

  • Vahed Ghiasi;Nur Irfah Mohd Pauzi;Shahab Karimi;Mahyar Yousefi
    • Geomechanics and Engineering
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    • v.34 no.3
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    • pp.267-284
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    • 2023
  • Landslides are one of the most dangerous phenomena and natural disasters. Landslides cause many human and financial losses in most parts of the world, especially in mountainous areas. Due to the climatic conditions and topography, people in the northern and western regions of Iran live with the risk of landslides. One of the measures that can effectively reduce the possible risks of landslides and their crisis management is to identify potential areas prone to landslides through multi-criteria modeling approach. This research aims to model landslide potential area in the Oshvand watershed using a support vector machine algorithm. For this purpose, evidence maps of seven effective factors in the occurrence of landslides namely slope, slope direction, height, distance from the fault, the density of waterways, rainfall, and geology, were prepared. The maps were generated and weighted using the continuous fuzzification method and logistic functions, resulting values in zero and one range as weights. The weighted maps were then combined using the support vector machine algorithm. For the training and testing of the machine, 81 slippery ground points and 81 non-sliding points were used. Modeling procedure was done using four linear, polynomial, Gaussian, and sigmoid kernels. The efficiency of each model was compared using the area under the receiver operating characteristic curve; the root means square error, and the correlation coefficient . Finally, the landslide potential model that was obtained using Gaussian's kernel was selected as the best one for susceptibility of landslides in the Oshvand watershed.

Boundaries and Differences in the Narrative of Passing: James W. Johnson and Nella Larsen (패싱, 경계와 차이의 서사 -제임스 W. 존슨과 넬라 라선)

  • Kang, Hee
    • Journal of English Language & Literature
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    • v.53 no.2
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    • pp.307-333
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    • 2007
  • When W. E. B. Du Bois says that "the problem of the twentieth century is the problem of the color line," such a statement clearly recognizes the significance of the issue of racial identity, a cultural phenomenon called 'passing.' Both Johnson in The Autobiography of an Ex-Colored Man and Larsen in Passing confront this issue. Both novels, using the metaphor of passing, not only trace the racial anxiety and race politics of the time but also expose the unstable landscape of the established social and cultural boundaries of racial identity. Mapping out multiple meanings and various dimensions of passing, this paper argues how Johnson's and Larsen's narratives display the ambivalence of color line while they at the same time complicate, problematize, and destabilize the mainstream racial boundaries and differences. It furthers to delineate how the two writers, with difference, deal with the problem of passing, the significance of racial identity, and black middle class values along with its intraracial differences. Rather than draw a clear definition of and a definitive closure on passing narrative, this paper focuses on its complexities and undecidability, challenging every dimension of its established significations. It also explores the complex dynamic between passing act and individual identity, for passing here is not just a racially signified term but extends its significance to the other factors of identity, such as class and even sexuality. Johnson and Larsen open up a site for a newly emergent, modern racial identity for black middle class in the twentieth century American urban spaces. Both writers, illuminating the subversive and slippery nature of language in their passing narrative, clearly herald new, different forms of Afro-American writings and themes for the different century they face.

A Literature Study on the Diagnostic Factors and Value as a Syndrome of Damjeok (담적의 진단요소 및 증후군으로서의 가치에 대한 문헌고찰)

  • Yun-Seo Lim;Gi-Hwan Rho;Gyu-Ho Choi;Sang-Hyun Lee;Seo-Hyung Choi
    • The Journal of Korean Medicine
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    • v.44 no.3
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    • pp.170-188
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    • 2023
  • Objectives: The purpose of this study is to investigate the diagnostic factors of Damjeok in the literature. Methods: This study used the databases of five (Mediclassics, RISS, KMbase, OASIS, CNKI) to analyze diagnostic factors of Damjeok. Literatures published by May 2023 were assessed and we classified 91 literatures dealing with diagnostic factors by 5 categories, 'characteristics', 'location', 'symptom', 'pulse wave & tongue feature', and 'eating habits & lifestyle'. Results: Damjeok is mainly formed at the stomach in the form of lump or hard seed, and it can be observed in other regions or even the whole body by its trait of floating. Damjeok mainly shows symptoms of the digestive system and also causes various symptoms associated with the respiratory system and infection, musculoskeletal system, urogenital system, neuropsychiatric system and cardiovascular system. Regarding pulse wave and tongue feature, a slippery wave and greasy coated tongue are typical features of Damjeok. Additionally, bad eating habits and a lack of exercise have been described as a factor that cause and aggravate Damjeok. Conclusions: The two most important factors in the diagnosis of Damjeok are abdominal stiffness by physical examination and digestive symptoms, and these correspond to the definition of a syndrome. Diagnostic factors based on literature evidence will provide clues to the clinical diagnosis of Damjeok syndrome.

Numerical Analysis of Steering Instability of 55kW Eletric Tractor by Bouncing and Sliding (Bouncing과 Sliding에 의한 55 kW급 전기 트랙터의 조향 불안정성 수치해석)

  • Yeong Su Kim;Jin Ho Son;Yu Jin Han;Seok Ho Kang;Hyung Gyu Park;Yong Gik Kim;Seung Min Woo;Yu Shin Ha
    • Journal of Drive and Control
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    • v.21 no.3
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    • pp.56-69
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    • 2024
  • Tractors are used for farming in harsh terrain such as slopes with slippery fields and steep passages. In these potentially dangerous terrain, steering instability caused by bouncing and sliding can lead to tractor rollover accidents. The center of gravity changes as parts such as engines and transmissions used in existing internal combustion engine tractors are replaced by motors and batteries, and the risk of conduction must be newly considered accordingly. The purpose of this study was to derive the center of gravity of a 55 kW class electric tractor using an electric platform from an existing internal combustion engine tractor, and to numerically investigate the tractor steering instability due to bouncing and sliding. The analysis provides a strong analysis by integrating an elaborate combination of a bouncing model and a sliding model based on Coulomb's theory of friction. Various parameters such as tractor speed, static coefficient of friction, bump length and radius of rotation are carefully analyzed through a series of detailed designs. In particular, the simulation results show that the cornering force is significantly reduced, resulting in unintended trajectory deviations. By considering such complexity, this study aims to secure optimal performance and safety in the challenging terrain within the agricultural landscape by providing valuable insights to improve tractor safety measures.