• Title/Summary/Keyword: work related flow

Search Result 208, Processing Time 0.025 seconds

Deformation characteristics at the contact boundary in cylinder compression process (원기둥 압축 공정에서 접촉 경계면의 변형 특성)

  • Min, Kyung-Ho;Ko, Byung-Du;Lee, Ha-Seong
    • Design & Manufacturing
    • /
    • v.8 no.2
    • /
    • pp.30-36
    • /
    • 2014
  • In this study, surface deformation patterns have been investigated by the rigid-plastic finite element method for friction factor test in solid cylinder compression process. AA1100 and AA6063 aluminum alloys, which show different work hardening characteristics respectively, have been adopted as model materials used for analysis. The main objective of this study is to provide the deformation mechanics in detail in solid cylinder compression process, especially at the die/workpiece interface that is closely related with the frictional conditions. For this reason, solid cylinder compression process has been numerically analyzed. The surface flow patterns at the contact boundary have been analyzed in terms of surface expansion, surface expansion velocity, pressure distributions exerted on the die surface along the die surface. By defining bulge factor, barreling phenomenon also have been examined with calibration curves to verify their effects on the surface flow pattern that is important for evaluating the frictional condition at the interface.

  • PDF

A Study on the Injection Characteristics of Urea Solution to Improve deNOx Performance of Urea-SCR Catalyst in a Heavy Duty Diesel Engine (대형 디젤 엔진용 요소분사 SCR촉매의 deNOx 성능향상을 위한 요소수용액의 분사특성 연구)

  • Jeong, Soo-Jin;Lee, Chun-Hwan
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.16 no.4
    • /
    • pp.165-172
    • /
    • 2008
  • Urea-SCR, the selective catalytic reduction using urea as reducing agent, has been investigated for about 10 years in detail and today is a well established technique for deNOx of stationary diesel engines. In the case of the SCR-catalyst a non-uniform velocity and $NH_3$ profile will cause an inhomogeneous conversion of the reducing agent $NH_3$, resulting in a local breakthrough of $NH_3$ or increasing NOx emissions. Therefore, this work investigates the effect of flow and $NH_3$ non-uniformities on the deNOx performance and $NH_3$ slip in a Urea-SCR exhaust system. From the results of this study, it is found that flow and $NH_3$ distribution within SCR monolith is strongly related with deNOx performance of SCR catalyst. It is also found that multi-hole injector shows better $NH_3$ uniformity at the face of SCR monolith face than one hole injector.

Cloud-based Healthcare data management Framework

  • Sha M, Mohemmed;Rahamathulla, Mohamudha Parveen
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.14 no.3
    • /
    • pp.1014-1025
    • /
    • 2020
  • Cloud computing services changed the way the data are managed across the healthcare system that can improve patient care. Currently, most healthcare organizations are using cloud-based applications and related services to deliver better healthcare facilities. But architecting a cloud-based healthcare system needs deep knowledge about the working nature of these services and the requirements of the healthcare environment. The success is based on the usage of appropriate cloud services in the architecture to manage the data flow across the healthcare system.Cloud service providers offer a wide variety of services to ingest, store and process healthcare data securely. The top three public cloud providers- Amazon, Google, and Microsoft offers advanced cloud services for the solution that the healthcare industry is looking for. This article proposes a framework that can effectively utilize cloud services to handle the data flow among the various stages of the healthcare infrastructure. The useful cloud services for ingesting, storing and analyzing the healthcare data for the proposed framework, from the top three cloud providers are listed in this work. Finally, a cloud-based healthcare architecture using Amazon Cloud Services is constructed for reference.

Multi-Objective Optimization of a Dimpled Channel Using NSGA-II (NSGA-II를 통한 딤플채널의 다중목적함수 최적화)

  • Lee, Ki-Don;Samad, Abdus;Kim, Kwang-Yong
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2008.03b
    • /
    • pp.113-116
    • /
    • 2008
  • This work presents numerical optimization for design of staggered arrays of dimples printed on opposite surfaces of a cooling channel with a fast and elitist Non-Dominated Sorting of Genetic Algorithm (NSGA-II) of multi-objective optimization. As Pareto optimal front produces a set of optimal solutions, the trends of objective functions with design variables are predicted by hybrid multi-objective evolutionary algorithm. The problem is defined by three non-dimensional geometric design variables composed of dimpled channel height, dimple print diameter, dimple spacing and dimple depth to maximize heat transfer rate compromising with pressure drop. Twenty designs generated by Latin hypercube sampling were evaluated by Reynolds-averaged Navier-Stokes solver and the evaluated objectives were used to construct Pareto optimal front through hybrid multi-objective evolutionary algorithm. The optimum designs were grouped by k-mean clustering technique and some of the clustered points were evaluated by flow analysis. With increase in dimple depth, heat transfer rate increases and at the same time pressure drop also increases, while opposite behavior is obtained for the dimple spacing. The heat transfer performance is related to the vertical motion of the flow and the reattachment length in the dimple.

  • PDF

Tunneling Magnetoresistance in Si/$SiO_2$/NiFe/$Al_2$$O_3$/Co Thin Films (Si/$SiO_2$/NiFe/$Al_2$$O_3$/Co 박막의 투과자기저항 특성 연구)

  • 현준원;백주열
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.14 no.11
    • /
    • pp.934-940
    • /
    • 2001
  • Magnetic properties were investigated for Si/SiO$_2$/NiFe(300 )/A1$_2$O$_3$(t)/Co(200 ) junction related with the parameters of $Al_2$O$_3$. Insulating $Al_2$O$_3$ layer was formed by depositing a 5~40 thick Al layer, followed by a 90~120s RF plasma oxidation in an $O_2$ atmosphere. Magnetoresistance was not observed for tunnel junction with 5~10 thick Al layer, but magnetoresistance was observed large for tunnel junction with 15~40 thick Al layer. Oxidation time did not largely influence magnetoresistance. Tunnel magnetoresistance effect depended on magnetization behavior of two ferromagnetic layers. Tunneling junction was confirmed through nonlinear I-V curve. In this work, tunneling magnetoresistance(TMR) up to 30 % was observed. This apparent TMR is an artifact of the nonuniform current flow over the junction in the cross geometry of the electrodes.

  • PDF

Modeling and Interoperability Test Case Generation of a Real-Time QoS Monitoring Protocol

  • Chin, Byoung-Moon;Kim, Sung-Un;Kang, Sung-Won;Park, Chee-Hang
    • ETRI Journal
    • /
    • v.21 no.4
    • /
    • pp.52-64
    • /
    • 1999
  • QoS monitoring is a kind of real-time systems which allows each level of the system to track the ongoing QoS levels achieved by the lower network layers. For these systems, real-time communications between corresponding transport protocol objects is essential for their correct behavior. When two or more entities are employed to perform a certain task as in the case of communication protocols, the capability to do so is called interoperability and considered as the essential aspect of correctness of communication systems. This paper describes a formal approach on modeling and interoperability test case generation of a real-time QoS monitoring protocol. For this, we specify the behavior of flow monitoring of transport layer QoS protocol, i.e., METS protocol, which is proposed to address QoS from an end-to-end's point of view, based on QoS architecture model which includes ATM net work in lower layers. We use a real-time Input/Output finite State Machine to model the behavior of real-time flow monitoring over time. From the modeled real-time I/OFSM, we generate interoperability test cases to check the correctness of METS protocol's flow monitoring behaviors for two end systems. A new approach to efficient interoperability testing is described and the method of interoperability test cases generation is shown with the example of METS protocol's flow monitoring. The current TTCN is not appropriate for testing real-time and multimedia systems. Because test events in TTCN are for message-based system and not for stream-based systems, the real-time in TTCN can only be approximated. This paper also proposes the notation of real-time Abstract Test Suite by means of real-time extension of TTCN. This approach gives the advantages that only a few syntactical changes are necessary, and TTCN and real-time TTCN are compatible. This formal approach on interoperability testing can be applied to the real-time protocols related to IMT-2000, B-ISDN and real-time systems.

  • PDF

Patient Flow Monitoring System based on Rheumatic Patient History Data (류머티스 환자 이력 데이터에 기반한 환자 플로우 모니터링 시스템)

  • Kim, Jun Woo;Lee, Sang Chul;Park, Sang Chan
    • The Journal of the Korea Contents Association
    • /
    • v.14 no.10
    • /
    • pp.10-19
    • /
    • 2014
  • In recent, hospital information systems are widely used to electronically record, manage and share the data collected in hospitals. Such systems have contributed greatly to improving the work efficiency in modern hospitals, however, the collected data concerning the patients should be appropriately processed and reused to provide the healthcare service providers with decision supports. Especially, this paper proposes the patient flow monitoring system for the operations management of the outpatient department for patients with chronic diseases, and discusses the related issues. The proposed system visualizes the standard process model extracted from the patient history data and various performance measures, and this enables the managers to evaluate and enhance the operations of the outpatient clinic. In this paper, the patient flow monitoring system is applied to the rheumatology clinic, and the prototype system optimized for I-pad is illustrated.

Prediction of Influent Flow Rate and Influent Components using Artificial Neural Network (ANN) (인공 신경망(ANN)에 의한 하수처리장의 유입 유량 및 유입 성분 농도의 예측)

  • Moon, Taesup;Choi, Jaehoon;Kim, Sunghui;Cha, Jaehwan;Yoom, Hoonsik;Kim, Changwon
    • Journal of Korean Society on Water Environment
    • /
    • v.24 no.1
    • /
    • pp.91-98
    • /
    • 2008
  • This work was performed to develop a model possible to predict the influent flow and influent components, which are one of main disturbances causing process problems at the operation of municipal wastewater treatment plant. In this study, artificial neural network (ANN) was used in order to develop a model that was able to predict the influent flow, $COD_{Mn}$, SS, TN 1 day-ahead, 2day-ahead and 3 day ahead. Multi-layer feed-forward back-propagation network was chosen as neural network type, and tanh-sigmoid function was used as activation function to transport signal at the neural network. And Levenberg-Marquart (LM) algorithm was used as learning algorithm to train neural network. Among 420 data sets except missing data, which were collected between 2005 and 2006 at field plant, 210 data sets were used for training, and other 210 data sets were used for validation. As result of it, ANN model for predicting the influent flow and components 1-3day ahead could be developed successfully. It is expected that this developed model can be practically used as follows: Detecting the fault related to effluent concentration that can be happened in the future by combining with other models to predict process performance in advance, and minimization of the process fault through the establishment of various control strategies based on the detection result.

Spatiotemporal chronographical modeling of procurement and material flow for building projects

  • Francis, Adel;Miresco, Edmond;Le Meur, Erwan
    • Advances in Computational Design
    • /
    • v.4 no.2
    • /
    • pp.119-139
    • /
    • 2019
  • Planning and management building projects should tackle the coordination of works and the management of limited spaces, traffic and supplies. Activities cannot be performed without the resources available and resources cannot be used beyond the capacity of workplaces. Otherwise, workspace congestion will negatively affect the flow of works. Better on-site management allows for substantial productivity improvements and cost savings. The procurement system should be able to manage a wider variety of materials and products of the required quality in order to have less stock, in less time, using less space, with less investment and avoiding multiple storage stations. The objective of this paper is to demonstrate the advantages of using the Chronographic modeling, by combining spatiotemporal technical scheduling with the 4D simulations, the Last Planner System and the Takt-time when modeling the construction of building projects. This paper work toward the aforementioned goal by examining the impact that material flow has on site occupancy. The proposed spatiotemporal model promotes efficient site use, defines optimal site-occupancy and workforce-rotation rates, minimizes intermediate stocks, and ensures a suitable procurement process. This paper study the material flow on the site and consider horizontal and vertical paths, traffic flows and appropriate means of transportation to ensure fluidity and safety. This paper contributes to the existing body of knowledge by linking execution and supply to the spatial and temporal aspects. The methodology compare the performance and procurement processes for the proposed Chronographic model with the Gantt-Precedence diagram. Two examples are presented to demonstrate the benefits of the proposed model and to validate the related concepts. This validation is designed to test the model's graphical ability to simulate construction and procurement.

Limit of interpreting 'security service' in current 「Security Services Industry Act」 and direction of legislating and revising private security industry (현행 「경비업법」상 경비개념과 경비업무 해석의 한계 및 민간보안산업 관련 입법의 제·개정 방향)

  • Choi, Eun-Ha;Kim, Na-Ri;Yoo, Young-Jae
    • Korean Security Journal
    • /
    • no.50
    • /
    • pp.35-57
    • /
    • 2017
  • Security Act has been partially revised many times since it was revised to "Security Service Act". Main contents of such revision consist of the addition of security work such as protection or special security, responsibility enforcement of security company or security guard and systematic management of security service based on security work of previous security service act. But, it needs to be checked out that the fundamental matter about the concept of 'security' is directly related as double-edged sword in such flow of legal revision. That is because security service satisfies the multiple needs for security in the modern risky society and is based on the concept of active management whose goal is to forster and develop the function of actual security service comparing that current "Security Service Act" regulates the formal security service whose goal is permission of security service and systematic management based on article 2 as previous facilities and manned security that is guard duty-centered security service in another respect. So, this study pointed out the limit of interpreting security and security service in "Security Services Industry Act" in respect of providing private security service and drew the conclusion that the legislation and efforts are required for 'security for citizen' by reinterpreting the legislation and revision of private security service-related law as the normal regulation of "Security Services Industry Act" and the special law of "Private Security Services Industry Act".

  • PDF