• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1077-1087
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• 2003

In this paper, we proposed an architecture of a cryptosystem with various operating modes for the network security and implemented in hardware using the ASIC library. For configuring a cryptosystem, the standard block ciphers such as AES, SEED and 3DES were included. And the implemented cryptosystem can encrypt and decrypt the data in real time through the wired/wireless network with the minimum latency time (minimum 64 clocks, maximum 256 clocks). It can support CTR mode which is widely used recently as well as the conventional block cipher modes such as ECB, CBC and OFB, and operates in the multi-bit mode (64, 128, 192, and 256 bits). The implemented hardware has the expansion possibility for the other algorithms according to the network security protocol such as IPsec and the included ciphering blocks can be operated simultaneously. The self-ciphering mode and various ciphering mode can be supported by the hardware sharing and the programmable data-path. The global operation is programmed by the serial communication port and the operation is decided by the control signals decoded from the instruction by the host. The designed hardware using VHDL was synthesized with Hynix 0.25$\mu\textrm{m}$ CMOS technology and it used the about 100,000 gates. Also we could assure the stable operation in the timing simulation over 100㎒ using NC-verilog.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1130-1135
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• 2015

The bond pull test is the most widely used technique for the evaluation and control of wire bond quality. The wire being tested is pulled upward until the wire or bond to the die or substrate breaks. The inspector test strength of wire by manually and it takes around 3 minutes to perform the test. In this paper, we develop a 3D vision system to measure 3D position of wire. It gives 3D position data of wire to move a hook into wires. The 3D measurement method to use here is a confocal imaging system. The conventional confocal imaging system is a spot scanning method which has a high resolution and good illumination efficiency. However, a conventional confocal systems has a disadvantage to perform XY axis scanning in order to achieve 3D data in given FOV (Field of View) through spot scanning. We propose a method to improve a parallel mode confocal system using a micro-lens and pin-hole array to remove XY scan. 2D imaging system can detect 2D location of wire and it can reduce time to measure 3D position of wire. In the experimental results, the proposed system can measure 3D position of wire with reasonable accuracy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.5
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• pp.325-335
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• 2018

We herein present a study on the active phased array antenna for receiving satellite broadcasting that can electrically align its polarization to that of target transmitters in its moving condition or in the Skew angle arrangement of the broadcasting satellite receiver. Hence, we have developed an active phased array structure composed of the self-developed Vivaldi antenna and multifunction core (MFC) chip, receiving RF front end module, and control units. In particular, the new Vivaldi antenna designed in the Ku-band of 10.7 - 14.5 GHz to receive one desired polarization mode such as the horizontal or vertical by means of an MFC chip and other control units that can control the amplitude and phase of each antenna element. The test results verified that cross-polarization property is 20 dB or higher and the primary beam can be scanned clearly at approximately ${\pm}60^{\circ}$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.173-180
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• 2017

The main objective of a torque controller below rated wind speed is to extract maximum power from the potential wind energy. To do this, the torque control method, which adjusts the torque magnitude and makes it proportional to the square of the generator speed, has been applied. However, this method makes the response slower as the wind turbines are getting larger in size with multi-MW capacities. In this paper, a torque control method that uses the nonlinear parameter of rotor speed for aerodynamic torque as a control gain is discussed to improve the response by adjusting an additional torque magnitude. The nonlinear parameter of the rotor speed could be calculated both online and offline. It is shown that the offline case is more practical and effective in producing power through the numerical simulation of a 2MW wind turbine by considering the real turbulence wind speed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.6
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• pp.1277-1286
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• 2013

Cloud computing's unique attributes such as elasticity, rapid provisioning and releasing, resource pooling, multi-tenancy, broad-network accessibility, and ubiquity bring many benefits to cloud adopters(company and organization), but also entails specific security risks associated with the type of adopted cloud and deployment mode. To minimize those types of risk, this paper proposed cloud computing security framework refered to strategic alliance model. The cloud computing security framework has main triangles that are cloud threat, security controls, cloud stakeholders and compose of three sides that are purposefulness, accountability, transparent responsibility. Main triangles define purpose of risk minimization, appointment of stakeholders, security activity for them and three sides of framework are principles of security control in the cloud computing, provide direction of deduction for seven service packages.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.5
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• pp.7-15
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• 2007

In wireless communication networks, single-radio single-channel architecture degrades throughput and end-to-end delay due to half-duplex transmission of wireless node and route intra interference. Also, In contention-based MAC (Medium Access Control) architecture, channel contention reduces throughput and packet collision enlarges end-to-end delay. In this paper, we use multi-radio multi-channel architecture which will make wireless node to operate in full duplex mode, and exclude route intra interference. Based on this architecture, we propose a new link metric, ccf which reflects the characteristics of a contention-based wireless link, and propose a routing path metric MCCR considering channel switching delay and route intra interference. MCCR is compared with MCR by simulation, the performance of a route established by MCCR outperforms the performance of a route by MCR in terms of throughput and end-to-end delay.

• Journal of Information Processing Systems
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• v.2 no.1
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• pp.39-43
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• 2006

In this paper, we proposed TASL-MAC, a medium-access control (MAC) protocol for wireless sensor networks. In wireless sensor networks, sensor nodes are usually deployed in a special environment, are assigned with long-term work, and are supported by a limited battery. As such, reducing the energy consumption becomes the primary concern with regard to wireless sensor networks. At the same time, reducing the latency in multi-hop data transmission is also very important. In the existing research, sensor nodes are expected to be switched to the sleep mode in order to reduce energy consumption. However, the existing proposals tended to assign the sensors with a fixed Sleep/Listening schedule, which causes unnecessary idle listening problems and conspicuous transmission latency due to the diversity of the traffic-load in the network. TASL-MAC is designed to dynamically adjust the duty listening time based on traffic load. This protocol enables the node with a proper data transfer rate to satisfy the application's requirements. Meanwhile, it can lead to much greater power efficiency by prolonging the nodes' sleeping time when the traffic. We evaluate our implementation of TASL-MAC in NS-2. The evaluation result indicates that our proposal could explicitly reduce packet delivery latency, and that it could also significantly prolong the lifetime of the entire network when traffic is low.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.2
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• pp.241-249
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• 2008

In this study, lateral vibration analysis has been conducted on a propulsion and lift shafting system for an air cushion vehicle using ANSYS code. The shafting system is totally flexible multi-elements system including air propeller, aluminum alloy of lift fan and thin walled shaft with flexible coupling. The analysis included the lateral natural frequencies, mode shapes and harmonic analysis of the shafting system taking into account three-dimensional models for propulsion and lifting shaft system. In case of ACV the yawing and pitching rate of craft will be quite high. During yawing and pitching of craft significant gyroscopic moment will be applied to the shafting and will generate high amplitude of lateral vibration. So, such a shafting system has very intricate lateral vibrating characteristics and natural frequencies of shafting must be avoided in the range of operating revolution. The control of lateral vibration is included in this study.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.38.1-38.1
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• 2016

TRAO has been newly equipped with a multi-beam receiver system, 16 pixel MMIC preamplifiers in a $4{\times}4$ array, a FFT spectrometer, and new control computer systems. In our new receiver systems one can make simultaneous observations with two molecular lines maximum 15 GHz apart with a spectral band width of 60 MHz. Typical system temperatures are about 160 - 200 K at 86 ~ 100 KHz and 400 - 500 K at 115 GHz in the dry weather. The new systems using On-The-Fly mode were found to be very efficient in making quick and sensitive maps of large clouds with a high velocity resolution (~0.04 km/s at 100 GHz). TRAO now calls for proposals for 2016 and 2017 observing season for everybody. In the talk we will introduce the current status of TRAO upgrade and its scientific preliminary results.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.5
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• pp.63-68
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• 2016

Audio mixer is an electronic device which performs a mixing of multiple audio signals. Digital mixer having various functions and scalability is spreaded thanks to advanced DSP and IT technology. However, digital mixer is more vulnerable to stability comparing to conventional analog mixer in the digital error or software error sense because its control is executed by SW. To solve this problem, in this paper, we propose a multi-channel digital analog hybrid mixer scheme, digital mixer error detection mechanism and malfunctioning switching technique. Also we develop the audio mixer having digital-analog hybrid structure. By simulation, we can sense the error of digital mixer except power loss in a 120ms, change into analog mixer mode automatically and provide continuous broadcasting function without mixer function loss.