• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.563-571
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• 2017

Test stand for altitude engine test of reciprocating engine was designed, manufactured and validated by preliminary test and simple calculation. These test stand designed to interface with Altitude turbo-shaft engine test facility of Korea Aerospace Research Institute. Many limiting condition for altitude test of reciprocating engine are assumed and test stand was developed to satisfy those limits. Test stand design specially focused on a altitude, Mach number and fuel temperature control for reciprocating engine altitude test with smaller air and fuel flow than turbo-shaft engine.

• Journal of Korea Multimedia Society
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• v.8 no.11
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• pp.1472-1482
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• 2005

In this paper, we propose a socket interface layer for large-scale multimedia servers that adopt TCP/IP Offload Engines (TOE). In order to provide legacy network applications with binary level compatibility, the socket interface layer intercepts all socket-related system calls to forward to either TOE or legacy TCP/IP Protocol stack. The layer is designed and implemented as a kernel module in Linux. The layer is located between BSD socket layer and INET socket layer, and passes the application's socket requests to INET socket layer or TOE. The layer provides multimedia servers and web servers with the following features: (1) All standard socket APIs and file I/O APIs that are supported (2) Support for binary level compatibility of existing socket programs (3) Support for TOE and legacy Ethernet NICs at the same time.

• KIISE Transactions on Computing Practices
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• v.24 no.3
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• pp.129-137
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• 2018

NVMe(Non-Volatile Memory Express) SSD(Solid State Drive) is a high-performance storage that makes use of flash memory as a storage cell, PCIe as an interface and NVMe as a protocol on the interface. It supports multiple I/O queues which makes it feasible to process parallel-I/Os on multi-core environments and to provide higher bandwidth than SATA SSDs. Hence, NVMe SSD is considered as a next generation-storage for data-center and cloud computing system. However, in the virtualization system, the performance of NVMe SSD is not fully utilized due to the bottleneck of the software I/O stack. Especially, when it uses I/O stack of the hypervisor or the host operating system like Xen and KVM, I/O performance degrades seriously due to doubled-I/O stack between host and virtual machine. In this paper, we propose a new I/O engine, called Direct-AIO (Direct-Asynchronous I/O) engine, that can access NVMe SSD directly for I/O performance improvements on QEMU emulator. We develop our proposed I/O engine and analyze I/O performance differences between the existed I/O engine and Direct-AIO engine.

• Tribology and Lubricants
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• v.16 no.4
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• pp.289-294
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• 2000

This paper present the contact stresses, which considers the shear stress at the cam and follower interface in the direct acting type valve train system of a high speed engine. To determine the contact condition, the normal contact forces are calculated by using the lumped mass dynamic modeling. The line contact is considered between the cam and follower interface. The variations of dynamic stresses are presented as a function of camshaft rotational angle. Also the effects of various design parameters are investigated.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.128-131
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• 2000

In this paper, the animated simulation system (Anisim) is proposed in order to develope an efficient functional system verification tool. It displays the simulation results of the designed system using graphic animation with various models lot the target system. With simple interface definitions given by the user, Anisim generates interface codes automatically. Users can describe and model the target system with the generated interface codes. Since the simulation engine is implemented in C-language, modeling is very simple and simulation can be performed in real time.

• Journal of the Korean Society of Safety
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• v.10 no.3
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• pp.21-29
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• 1995

The automotive transmission is the principal component of the power transmission system which converts the engine power into the adjustable power for the vehicle driving system. To the unskilled driver the automization of transmission is required for the safety and fuel economy. In this study, the dynamic model of the automotive power transmission system was presented and simulation program and interface board which interface IBM-PC with ECU was devloped. Through the traveling simulation by interfacing ECU with simulation program, the shifting transients are investigated. For verification of simulation experiment was carried out, the results of simulation was agreed well with those of simulation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.6
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• pp.624-629
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• 2014

The purpose of this study is to carry out the task of engine hesitation which occurred intermittently in driving due to the defective CKPS of LPI vehicles. As the result of the wrong data from the equipment of D-logger, the signal error of CKPS caused the engine hesitation. We performed a study in the followings to analyze and investigate the cause effectively. First, we have investigated the control wiring harness and connector pin contact defect inspection. Second, we have inspected the defection of CKPS separately. From this study, it was found that the engine hesitation were caused by the bad durability and we have showed how to diagnosis the fault of the engine hesitation intermittently while driving. Therefore, it is determined that we have to improve the durability of the CKPS through a strict quality control and to increase the reliability.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.3
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• pp.98-109
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• 2000

A new PC-based Engine Control system (ECS) is developed using an object oriented programming method. This system provides more convenient environment for engine tests, easier user interface and extended functions. A Windows-based ECS software is developed with class, and the class structure is built on encapsulation and abstraction. The closed-loop engine control scheme can be easily constructed by using dynamic link library and multitasking. This means that a user can perform desired experiments without clear knowledge of the hardware structure of the ECS. Also this system allows a user to individually control the ignition and fuel injection for each cylinder in a simple manner such as through a keyboard/mouse or in a real-time operation from a closed-loop control program.

• Journal of KIISE:Information Networking
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• v.37 no.1
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• pp.57-65
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• 2010

Recently, the character recognization technique is strongly needed to enable the mobile communication devices with cameras to gather input information from the users. In general, it is not easy to reuse a CBOCR(Camera Based Optical Character Recognizer) module because of its dependency on a specific platform. In this paper, we propose a software architecture for CBOCR module providing the easy adaptability to various mobile communication platforms. The proposed architecture is composed of the platform dependency support layer, the interface layer, the engine support layer, and the engine layer. The engine layer adopts a plug-in data structure to support various hardware endian policies. We show the effectiveness of the proposed method by applying the architecture to a practical product.

• The KSFM Journal of Fluid Machinery
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• v.18 no.6
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• pp.37-44
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• 2015

Conjugate heat analysis on a high pressure turbine stage including secondary flow paths has been carried out. The secondary flow paths were designed to be located in front of the nozzle and between the nozzle and rotor domains. Thermal boundary conditions such as empirical based temperature or heat transfer coefficient were specified at nozzle and rotor solid domains. To create heat transfer interface between the nozzle solid domain and the rotor fluid domain, frozen rotor with automatic pitch control was used assuming that there is little temperature variation along the circumferential direction at the nozzle solid and rotor fluid domain interface. The simulation results showed that secondary flow injected from the secondary flow path not only prevents main flow from penetrating into the secondary flow path, but also effectively cools down the nozzle and rotor surfaces. Also thermal barrier coating with different thickness was numerically implemented on the nozzle surface. The thermal barrier coating further reduces temperature gradient over the entire nozzle surface as well as the overall temperature level.