• Title/Summary/Keyword: contact point

Search Result 1,219, Processing Time 0.03 seconds

Coupling Framework of Hair with FLIP Solver for Representing Spray Motion of Liquid in Wet Hair (젖은 헤어에서 분사된 액체의 움직임을 표현하기 위한 FLIP 해법과 헤어의 결합 프레임워크)

  • Kim, Jong-Hyun
    • Journal of the Korea Computer Graphics Society
    • /
    • v.25 no.4
    • /
    • pp.1-8
    • /
    • 2019
  • In this paper, we propose a new framework that can express the detailed movement of liquid sprayed from wet hair or fur. In wet hair, not only the friction and adhesion of the hair but also the movement of the liquid has a distinctive motion compared to the dry hair. However, the recently proposed techniques only considered the contact force and friction of the hair and did not improve the movement of the liquid dispersed in the wet hair. This problem is detrimental to the quality of the result because it does not capture the detailed features expressed in the interaction of hair and liquid. The main point of this paper is to alleviate this problem and improve the quality of the result. As a result, we propose a combining framework that can efficiently express FLIP (Fluid-implicit particle) based fluid simulation and interaction of hair particles. The proposed method expresses the movement of the liquid sprayed in a curved shape which was not expressed in previous studies.

Vector form intrinsic finite-element analysis of static and dynamic behavior of deep-sea flexible pipe

  • Wu, Han;Zeng, Xiaohui;Xiao, Jianyu;Yu, Yang;Dai, Xin;Yu, Jianxing
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.12 no.1
    • /
    • pp.376-386
    • /
    • 2020
  • The aim of this study was to develop a new efficient strategy that uses the Vector form Intrinsic Finite-element (VFIFE) method to conduct the static and dynamic analyses of marine pipes. Nonlinear problems, such as large displacement, small strain, and contact and collision, can be analyzed using a unified calculation process in the VFIFE method according to the fundamental theories of point value description, path element, and reverse motion. This method enables analysis without the need to integrate the stiffness matrix of the structure, because only motion equations of particles established according to Newton's second law are required. These characteristics of the VFIFE facilitate the modeling and computation efficiencies in analyzing the nonlinear dynamic problem of flexible pipe with large deflections. In this study, a three-dimensional (3-D) dynamical model based on 3-D beam element was established according to the VFIFE method. The deep-sea flexible pipe was described by a set of spatial mass particles linked by 3-D beam element. The motion and configuration of the pipe are determined by these spatial particles. Based on this model, a simulation procedure to predict the 3-D dynamical behavior of flexible pipe was developed and verified. It was found that the spatial configuration and static internal force of the mining pipe can be obtained by calculating the stationary state of pipe motion. Using this simulation procedure, an analysis was conducted on the static and dynamic behaviors of the flexible mining pipe based on a 1000-m sea trial system. The results of the analysis proved that the VFIFE method can be efficiently applied to the static and dynamic analyses of marine pipes.

Optimization and modification of PVDF dual-layer hollow fiber membrane for direct contact membrane distillation; application of response surface methodology and morphology study

  • Bahrami, Mehdi;Karimi-Sabet, Javad;Hatamnejad, Ali;Dastbaz, Abolfazl;Moosavian, Mohammad Ali
    • Korean Journal of Chemical Engineering
    • /
    • v.35 no.11
    • /
    • pp.2241-2255
    • /
    • 2018
  • RSM methodology was applied to present mathematical models for the fabrication of polyvinylidene fluoride (PVDF) dual-layer hollow fibers in membrane distillation process. The design of experiments was used to investigate three main parameters in terms of polymer concentration in both outer and inner layers and the flow rate of dope solutions by the Box-Behnken method. According to obtained results, the optimization was done to present the proper membrane with desirable properties. The characteristics of the optimized membrane (named HF-O) suggested by the Box-Behnken (at the predicted point) showed that the proposed models are strongly valid. Then, a morphology study was done to modify the fiber by a combination of three types of a structure such as macro-void, sponge-like and sharp finger-like. It also improved the hydrophobicity of outer surface from 87 to $113^{\circ}$ and the mean pore size of the inner surface from 108.12 to 560.14 nm. The DCMD flux of modified fiber (named HF-M) enhanced 62% more than HF-O when it was fabricated by considering both of RSM and morphology study results. Finally, HF-M was conducted for long-term desalination process up to 100 hr and showed stable flux and wetting resistance during the test. These stepwise approaches are proposed to easily predict the main properties of PVDF dual-layer hollow fibers by valid models and to effectively modify its structure.

Southeast Asian Studies in Korea Revisited: Pluralistic Growth and Lack of Inclusiveness (한국의 동남아연구 성장과 포괄성 문제)

  • JEON, Je Seong
    • The Southeast Asian review
    • /
    • v.28 no.4
    • /
    • pp.1-29
    • /
    • 2018
  • The purpose of this study is to review the Southeast Asian studies in Korea in a comprehensive way and to set a new task for our academic community. To do this, I tried to analyze the total amount and trends of scholarly achievement (thesis, journal articles, and academic books). The content is divided into research history, research accumulation, and researcher scale. The history of research dates back more than we thought and was decentralized. Research accumulation is becoming more and more pluralistic. The number of researchers from various academic fields was higher than expected. The newly discovered Southeast Asian studies of Korea suggests the task of increasing the inclusiveness of our academic community. The KASEAS (Korean Association of Southeast Asian Studies) seems to be narrow and stagnant compared to the trend of Southeast Asian studies in Korea, which is constantly growing quantitatively, academically spreading, and transcending nationality. In order to increase the inclusiveness of the KASEAS, efforts should be made to open a variety of decentralized and autonomous study groups, to invite domestic graduate students from Southeast Asia, and to spread the university's foothold as a point of contact between pluralistic disciplines.

A Study on RFID Privacy Protection in Insecure Channel (안전하지 않은 채널에서의 RFID 프라이버시 보호에 관한 연구)

  • Park Jang-Su;Lee Im-Yeong
    • Journal of the Korea Institute of Information Security & Cryptology
    • /
    • v.16 no.3
    • /
    • pp.77-86
    • /
    • 2006
  • As a core technology in the ubiquitous environment, RFID (Radio Frequency Identification) technology takes an important role. RFID technology provides various information about objects or surrounding environment by attaching a small electronic tag on the object, thus, it means the remote control recognition technology. However, the problems which never happened before can be generated on the point of security and privacy due to the feature that RFID technology can recognize the object without any physical contact. In order to solve these problems, many studies for the RFID recognition technology are going on the progress. The currently running study is the secure communication channel between database and reader applying the recognition technology in the insecure communication channel between reader and tag. But, the purpose of this paper is to settle a privacy problem, which is insecurity of communication between database and reader channel by suggesting providing a user with authentication protocol in order to give information to an authorized entity.

Development of a process to apply uniform pressure to bond CFRP patches to the inner surface of undercut-shaped sheet metal parts (언더컷 형상의 판재 성형품에 보강용 CFRP 패치의 접합을 위한 공정기술 개발)

  • Lee, Hwan-Ju;Jeon, Yong-Jun;Cho, Hoon;Kim, Dong-Earn
    • Design & Manufacturing
    • /
    • v.14 no.4
    • /
    • pp.65-70
    • /
    • 2020
  • Partial reinforcement of sheet metal parts with CFRP patch is a technology that can realize ultra-lightweight body parts while overcoming the high material cost of carbon fiber. Performing these patchworks with highly productive press equipment solves another issue of CFRP: high process costs. The A-pillar is the main body part and has an undercut shape for fastening with other parts such as roof panels and doors. Therefore, it is difficult to bond CFRP patches to the A-pillar with a general press forming tool. In this paper, a flexible system that applies uniform pressure to complex shapes using ceramic particles and silicone rubber is proposed. By benchmarking various A-pillars, a reference model with an undercut shape was designed, and the system was configured to realize a uniform pressure distribution in the model. The ceramic spherical particles failed to realize the uniform distribution of high pressure due to their high hardness and point contact characteristics, which caused damage to the CFRP patch. Compression equipment made of silicone rubber was able to achieve the required pressure level for curing the epoxy. Non-adhesion defects between the metal and the CFRP patch were confirmed in the area where the bending deformation occurred. This defect could be eliminated by optimizing the process conditions suitable for the newly developed flexible system.

A Study on the Customer Experience Design through analyzing Smart Hotels in China (중국 스마트 호텔의 사례 연구를 통한 사용자 경험 연구)

  • Luo, Xuan;Pan, Yonghwan
    • Journal of the Korea Convergence Society
    • /
    • v.12 no.3
    • /
    • pp.115-124
    • /
    • 2021
  • The outbreak of covid-19 has brought the characteristics and advantages of non-contact services to increased prominence, and the development of smart hotels"has accelerated. This study aims to identify, categorize and define the smart service experience at different touch points of the customer experience. The concept and characteristics of the smart hotel were examined based on existing research and literature. An analytical framework was designed using smart experience factors and customer touch points of smart hotels. Selected Chinese smart hotels were then examined under this framework. The case analysis results show that the customer experience design of smart hotels has developed to different degrees, in terms of interactivity, personalization, accessibility, information and privacy security. Based on the above findings, this article suggests that the design of smart hotels should use integrated data to further enhance personalized service experience.

Cybersecurity of The Defense Information System network connected IoT Sensors (IoT Sensor가 연결된 국방정보통신망의 사이버보안 연구)

  • Han, Hyun-Jin;Park, Dea-Woo
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.24 no.6
    • /
    • pp.802-808
    • /
    • 2020
  • The IoT(Internet of Things) is based on the development of sensor technology and high-speed communication infrastructure, and the number of IoT connected to the network is increasing more than the number of people, and the increase is also very fast. In the field of defense, IoT is being deployed in various fields such as operations, military, base defense, and informatization, and the need is also increasing. Unlike the existing PC/server information protection system, cyber threats are also increasing as IoT sensors, which are vulnerable to information protection, are increasing in the network, so it is necessary to study the platform to protect the defense information and communication network. we investigated the case of connecting wired and wireless IoT to the defense network, and presented an efficient interlocking design method of the IoT integrated independent network with enhanced security by minimizing the contact point with the defense network.

A Study on Optimization of Picking Facilities for e-Commerce Order Fulfillment (온라인 주문 풀필먼트를 위한 물류센터 피킹 설비 최적화에 대한 연구)

  • Kim, TaeHyun;Song, SangHwa
    • The Journal of Society for e-Business Studies
    • /
    • v.26 no.1
    • /
    • pp.67-78
    • /
    • 2021
  • The number of domestic e-commerce transactions has been breaking its own record by an annual average growth rate of over 20% based on volume for the past 5 years. Due to the rapid increase in e-commerce market, retail companies that have difficulty meeting consumers in person are in fierce competition to take the lead in the last mile service, which is the only point of contact with customers. Especially in the delivery area, where competition is most intense, the role of the fulfillment center is very important for service differentiation. It must be capable of fast product preparation ordered by consumers in accordance with the delivery service level. This study focuses on the order picking system for rapid order processing in the fulfillment center as an alternative for companies to gain competitive advantage in the e-commerce market. A mixed integer programming model was developed and implemented to optimize the stock replenishment in order picking facilities. The effectiveness was scientifically and objectively verified by simulation using the actual operation process and data.

Diagnostic Methods of Respiratory Virus Infections and Infection Control (호흡기 바이러스 감염의 진단법과 감염관리)

  • Park, Chang-Eun
    • Korean Journal of Clinical Laboratory Science
    • /
    • v.53 no.1
    • /
    • pp.11-18
    • /
    • 2021
  • Respiratory viruses (RVs) cause infections in hospital environments through direct contact with infected visitors. In infection control, it causes major problems of acquired infections in hospitals by respiratory viruses. The surveillance data derived from clinical laboratories are often used to properly allocate medical resources to hospitals and communities for treatment, consumables, and diagnostic product purchases in the institutions and public health sectors that provide health care. An early diagnosis is essential in infection with respiratory viruses, and methods that can be used in diagnostic methods using respiratory samples include virus culture, molecular diagnosis, and analysis. A microchip provides a new strategy for developing a more diverse and powerful technology called point-of-care testing. The importance of the respiratory system should be applied strictly to the infection control guidelines to ensure the occupational health and safety of health care workers. Evidence of clinical efficacy, including this study, is challenging the long-standing paradigm for infection propagation. Additional assistance will be needed for frequent tests to detect respiratory viruses in inpatients who have begun to show new respiratory symptoms indicating infections requiring efforts to control the infection.