• KNOM Review
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• v.21 no.2
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• pp.35-45
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• 2018

As Network Slicing functionality gets applied to mobile networking, a mechanism that enables the selection of network slices becomes indispensable. Following the 3GPP Technical Specification for the 5G Architecture, the inclusion of the Network Slice Selection Function (NSSF) in order to leverage the process of slice selection is apparent. However, actual implementation of this network function needs to deal with the dynamic changes of network instances, due to this, a platform that supports the orchestration of Virtual Network Functions (VNF) is required. Our proposed solution include the use of the Central Office Rearchitected as a Data Center (CORD) platform, with the specified profile for mobile networks (M-CORD) that integrates a service orchestrator (XOS) alongside solutions oriented to Software Defined Networking (SDN), Network Function Virtualization (VNF) and virtual machine management through OpenStack, in order to provide the right ecosystem where our implementation of NSSF can obtain slice information dynamically by relying on synchronization between back-end services and network function instances.

• Fire Science and Engineering
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• v.24 no.2
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• pp.97-105
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• 2010

The smoke control systems using pressure differentials are already well known as the most reliable method to prevent the smoke infiltration into the emergency stairs or safe spaces. However, it is true that many problems are domestically pointed out due to the insufficient understanding and technology on the smoke control systems using pressure differentials. In this regard, this work analyzed the effect of major factors for smoke control system using pressure differentials such as a duct area, opening area of air supply damper, improvement on open vestibules, stack effect and location of air supply. In conclusion, adequate pressure differentials can not be maintained in small duct because the smaller duct area have the large friction loss. Especially, It is confirmed that the major factor for deterioration of smoke control system performance is stack effect that makes pressure differentials smaller in the lower floors.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.4
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• pp.127-134
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• 2023

This paper describes how to port the eCos operating system and PROFINET communication stack developed based on gcc to the IAR compiler. The eCos operating system provides basic functions such as multi-thread, TCP/IP, and device driver for PROFINET operation, so there is no need to change it when developing PROFINET applications. Therefore, in this study, we reuse an eCos library built with gcc and it link with PROFINET communication stack that are ported to IAR complier. Due to the different of the gcc and IAR linker, symbol definitions and address of the constructors should be changed using the external tool that generates symbol definitions and address of the constructors from MAP file. In order to verify the proposed method, it was confirmed that the actual I/O was operating normally through PROFINET IRT communication by connecting to the Siemens PLC. IAR compiler has better performance in both the compile time and the size of the generated binary. The proposed method in this study is expected to help port various open sources as well as eCos and PROFINET communication stacks to other compilers.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.260-263
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• 2005

The effects of internal manifold designs the reactant feed-stream in Polymer Electrolyte Fuel Cells (PEFCs) is studied to figure out mass flow-distribution patterns over an entire fuel cell stack domain. Reactants flows are modeled either laminar or turbulent depending on regions and the open channels in the bipolar plates are simulated by porous media where permeability should be pre-determined for computational analysis. In this work, numerical models for reactant feed-stream in the PEFC manifolds are classified into two major flow patterns: Z-shape and U-shape. Several types of manifold geometries are analyzed to find the optimal manifold configurations. The effect of heat generation in PEFC on the flow distribution is also investigated applying a simplified heat transfer model in the stack level (i.e. multi-cell electrochemical power-generation unit). This modeling technique is well suited for many large scale problems and this scheme can be used not only to account for the manifold flow pattern but also to obtain information on the optimal design and operation of a PEMC system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.7
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• pp.343-350
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• 2014

Regardless of the building design scenarios, evaluation of high-rise buildings required to have smoke-proof enclosures that are provided with a smoke management system. The goal of the smoke management system design is to make sure the pressure differentials at every story within the building fall within the allowable pressure range. If the minimum design pressure is not met, smoke may enter the stair. If the provided pressure is too great, it becomes difficult for occupants to open the doors, while attempting to egress. Ensuring that the pressure differential between the vestibule and the floor is within the prescribed range becomes challenging, due to natural effects on the building, such as the stack effect. In this research, smokeproof enclosure design scenarios were evaluated; and as a result, separation levels for compartmentation were deduced, in the balancing of pressurized-vestibule smoke control systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.18-38
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• 2017

Infrastructure-as-a-Service (IaaS) clouds provide infrastructure as a pool of virtual resources, and the public IaaS clouds, e.g. Amazon Web Service (AWS) and private IaaS cloud toolkits, e.g. OpenStack, CloudStack, etc. provide their own application programming interfaces (APIs) for managing the cloud resources they offer. The heterogeneity of the APIs, however, makes it difficult to access and use the multiple cloud services concurrently and collectively. In this paper, we explore previous efforts to solve this problem and present our own implementation of an integrated cloud API, which can make it possible to access and use multiple clouds collectively in a uniform way. The implemented API provides a RESTful access and hides underlying cloud infrastructures from users or applications. We show the implementation details of the integrated API and performance evaluation of it comparing the proprietary APIs based on our cloud testbed. From the evaluation results, we could conclude that the overhead imposed by our interface is negligibly small and can be successfully used for multi-cloud access.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.131-134
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• 2020

스마트시티로 가는 첫걸음이자 핵심이라 할 수 있는 IoT 기술이 우리의 삶을 변화시키고 있다. 원격에서 집 내부의 상태를 확인하며 조정할 수 있고, 집 내부의 상황도 영상을 통해 확인할 수 있게 되었다. 이처럼 IoT 기술은 우리 삶의 편리함을 제공하고 중요한 요소가 되었지만, IoT 환경 관리의 주체가 사용자 개인이거나 IoT 환경상태를 모니터링하며 관리할 수 있는 수단이 없어 관리가 되지 않고 있고 공격을 받아도 사용자가 알 수 없다는 특성 때문에 IoT 보안에 있어 심각한 문제를 일으킬 수 있다. 이러한 문제에도 불구하고 IoT 보안에 대한 인식과 IoT 환경에 특화된 관리 시스템은 갖춰지지 않고 있다. 본 논문에서는 오픈 소스 데이터 분석 및 시각화 솔루션인 Elastic Stack을 활용하여 손쉽게 IoT 환경을 관리하고 상태를 시각화하여 제공하는 IoT 환경 관리 시스템을 제안한다.

• Journal of KIBIM
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• v.9 no.4
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• pp.62-74
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• 2019

Because the existing BIM platform is based on user services, the focus is on the development of SaaS (Software as a Service), which provides business services online. However, since a harbor is a security facility, the harbor BIM platform is preferably provided in a private form, rather than relying on the infrastructure environment provided by external cloud providers. Therefore, this study analyzes and reviews the main functions to be provided as SaaS services of the harbor BIM platform. The goal is to build a cloud-based harbor BIM platform that can provide this service to users. To this end, we built IaaS (Infrastructure as a Service) environment of the harbor BIM platform based on the open source Open Stack and integrate and develop PaaS environment with Open Shift applied with IaaS. We applied the GPU to the harbor BIM platform to verify the performance of the harbor BIM platform, and found that the rendering and loading times are improved. In particular, it is expected to reduce the cost of introduction and provide it as the basic cloud environment of similar BIM platform for infrastructure facilities.

• Journal of IKEEE
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• v.19 no.3
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• pp.319-326
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• 2015

This paper proposes method about development of conversion software for controller without OPC stack to communicate with OPC DA client. The proposed method is composed of development of OPC server based on OPC DA standard protocol, development of GUI application can be checked the OPC tag and point informations, development of conversion module to convert from OPC protocol to open standard protocol. In the stage of development of OPC server based on OPC DA standard protocol, we develope server in the pc to transmit and receive datum through OPC DA protocol with OPC DA client. In the stage of evelopment of GUI application can be checked the OPC tag and point informations, run the OPC DA server and register to window system registry and check OPC tags, points, transmitting and receiving of data from serial communication. In the stage of development of conversion module to convert from OPC protocol to open standard protocol, convert from OPC tag data which has received from OPC DA client to protocol can be communicated with industrial controller using open standard protocol so that support to transmit and receive data. To evaluate the efficiency of the proposed software, we connected OPC DA server software and OPC client, and 5 sample industrial controller which use open standard protocol, as a result we got 96.98% average communication succeeding rate among entire transmitting and receiving packets. We also confirmed that successfully communicated between industrial building controller which uses modbus protocol and industrial OPC DA client using OPC DA conversion software proposed by this dissertation.

• Asian-Australasian Journal of Animal Sciences
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• v.1 no.4
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• pp.201-208
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• 1988

Fifty-six lactating Surti buffaloes, fed rice straw, were allocated to seven treatment groups as follows: 1. Straw supplemented with 2% urea (SS) + 1.5kg rice bran (RB) 2. Straw treated with 4% urea in an open stack (TS open) 3. TS open + 1.5 kg RB 4. TS open + 3.0 kg RB 5. TS open + 1.5 kg RB + 3.0 kg Gliricidia (Gl) 6. Straw treated with 4% urea in a closed pit (TS closed) 7. TS closed + 1.5 kg RB + 3.0 kg Gl Milk production, butterfat percentage and liveweight gain of cows and calves were measured and tested with analysis of variance. The results are: - The animals on urea treated straw (group 2) had a higher milk production (p<0.05), higher butterfat production (p<0.05) and less liveweight gain loss (p<0.05) than the animals on urea supplemented straw (group 1). Butterfat percentage also increased by treatment, although not significantly (p>0.05). - Increasing levels of rice bran (groups 3 and 4 compared to 2) increased total milk production and milked quantity of butterfat, while butterfat percentage decreased (p < 0.05). - Milk production increased (p <0.05) with extra rice bran added (group 4 compared to 3), but was not affected (p > 0.05) by Gliricidia addition (group 5 compared to 3). Butterfat percentage dropped with extra rice bran supplement (p <0.05). The lack of response to Gliricidia indicated that protein is not limiting in treated straw, or that Gliricidia protein is partly insoluble. - System of treatment had no effect on milk production (p >0.05), while supplementation with 1.5 kg RB and 3.0 kg Gliricidia increased production and caused a lower butterfat percentage (p <0.05) (groups 2, 5, 6 and 7 compared). A significant (p <0.05) interaction treatment system x supplementation was present. It was concluded, that both treatment and supplementation did affect milk production as well as milk composition. Gliricidia addition gave less effect than rice bran, indicating different requirements for starchy substances in the feed. Treatment of straw does not negatively affect butterfat production, it can increase butterfat production and even butterfat percentage.