• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.274.1-274.1
• /
• 2013

We report the circumferential alignment of human aortic smooth muscle cells (HASMCs) in an orthogonally micropatterned circular microfluidic channel to form an in vivo-like smooth muscle cell layer. To realize a biomimetic smooth muscle cell layer which is aligned perpendicular to the axis of blood vessel, we first fabricated a half-circular polydimethylsiloxane (PDMS) microchannel by soft lithography using a convex PDMS mold. The orthogonally micro wrinkle patterns were generated inside the half-circular microchannel by stretching-releasing operation under UV irradiation. Upon UV treatment with uniaxial 40 % stretch of a PDMS substrate and releasing process, the microwrinkle patterns perpendicular to the axial direction of the circular microchannel were generated, which could guide the circumferential alignment of HASMCs successfully during cultivation. The analysis of orientation angle, shape index, and contractile protein marker expression indicates that the cultured HASMCs revealed the in vivo-like cell phenotype. Finally, we produced circular microchannels by bonding two half-circular microchannels, and cultured the HASMCs circumferentially with high alignment and viability for 5 days. These results are the first demonstration for constructing an in vivo-like 3D smooth muscle cell layer in the circular microfluidic channel which can provide novel bioassay platforms for in-depth study of HASMC biology and vascular function.

• Journal of Advanced Marine Engineering and Technology
• /
• v.28 no.1
• /
• pp.90-97
• /
• 2004

DC motor requires a rotor speed sensor for accurate speed control. The speed sensors such as resolvers and encoders are used as speed detectors. but they increase cost and size of the motor and restrict the industrial drive applications. So in these days. many Papers have reported on the sensorless operation or DC motor(3)-(5). This paper Presents a new sensorless strategy using neural networks(6)-(8). Neural network structure has three layers which are input layer. hidden layer and output layer. The optimal neural network structure was tracked down by trial and error and it was found that 4-16-1 neural network has given suitable results for the instantaneous rotor speed. Also. learning method is very important in neural network. Supervised learning methods(8) are typically used to train the neural network for learning the input/output pattern presented. The back-propagation technique adjusts the neural network weights during training. The rotor speed is gained by weights and four inputs to the neural network. The experimental results were found satisfactory in both the independency on machine parameters and the insensitivity to the load condition.

• Journal of Power Electronics
• /
• v.19 no.4
• /
• pp.989-999
• /
• 2019

This paper proposes a fault-tolerant control strategy with finite control set model predictive control (FCS-MPC) based on hierarchical optimization for five-level H-bridge neutral-point-clamped (5L-HNPC) inverter-fed induction motor drives. Fault-tolerant operation is analyzed, and the fault-tolerant control algorithm is improved. Adopting FCS-MPC based on hierarchical optimization, where the voltage is used as the controlled objective, called model predictive voltage control (MPVC), the postfault controller is simplified as a two layer control. The first layer is the voltage jump limit, and the second layer is the voltage following control, which adopts the optimal control strategy to ensure the current following performance and uniqueness of the optimal solution. Finally, simulation and experimental results verify that 5L-HNPC inverter-fed induction motor drives have strong fault tolerant capability and that the FCS-MPVC based on hierarchical optimization is feasible.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.14 no.3
• /
• pp.63-73
• /
• 2004

This paper proposes an efficient authentication scheme for multicast packet using recovery layer to provide source authentication. The problems of the existing schemes are as follows ： TESLA requires time synchronization between the sender and the receiver, md hash-based schemes have high communication overheads due to additional hash values and require many buffers and delay for verification on receivers. Our main focus is reducing the buffer size, communication and computation burden of the receiver. The proposed scheme in this paper is highly robust to packet loss using the recovery layer based on XOR operation. It also provides low communication overhead, low verification cost, non-repudiation of the origin, immediate verification and robustness against DoS attack on the receiver.

• Nuclear Engineering and Technology
• /
• v.55 no.1
• /
• pp.12-24
• /
• 2023

With the improvement of laser technology, the strategic needs of efficient and precise decontamination of various components in nuclear application units can be fulfilled by laser decontamination. The surface contaminants of nuclear facilities mainly exist both as loose contaminated layer and fixed oxide layer. The types of radionuclides and contamination layer thickness are closely related to the operation status of nuclear facilities, which have an important influence on the laser decontamination process. This study reviewed the mechanism of laser surface treatment and the influence of laser process parameters on the decontamination thickness, decontamination factor, decontamination efficiency and the distribution of aerosol particle. Although multiple studies have been performed on the mechanism of laser processing and laser decontamination process, there are few studies on the microscopic process mechanism of laser decontamination and the influence of laser decontamination on surface properties. In particular, the interaction between laser and radioactive contaminants needs more research in the future.

• Journal of Practical Engineering Education
• /
• v.11 no.1
• /
• pp.33-41
• /
• 2019

A pavement construction process consists of series of lay-down operation for pavement materials to form a designated thickness and compaction operation for the lay-down layer to form a designated strength. A technological breakthrough in pavement compaction equipment was made in last 15 years in western countries: intelligent compaction roller, that is equipped with GPS along with other pavement response sensors is becoming a game-changer in pavement construction. This paper introduces AR system that may be used in asphalt pavement compaction operation using intelligent compactor. Since AR technology is very new concept in road construction society, a suggestion for accompanying education program was also made for specific task group in pavement compaction operation. Since AR technology has not been introduced in asphalt pavement compaction operation, the AR compaction management would lead the construction quality of asphalt pavement to the beyond level.

• Applied Microscopy
• /
• v.28 no.3
• /
• pp.307-314
• /
• 1998

The author has undertaken this study for demonstrating the relationship between keratinization and proliferation as well as remodeling of epidermis. Healthy ICR strain male mice, weighing about $20\sim25gm$, were used as experimental animals. Under the general anesthesia with ether the skins of experimental animals were subjected to a dorsal, transverse, full-thickness incision with 0.5cm in length, and removed them on 3rd day, 7th day and 2nd week after operation Specimens were prepared for electron microscopic study. The results obtained were as follows: The epidermis of 3rd day group is made up of $7\sim8$ keratinocytes. The new epidermal cells are grown beneath the necrotic tissue. Keratohyaline granules (KHGs) are visible in some granular cells. Various sited-KHGs are seen in granular layer cell, and in spinous cell ribosomes, tonofilaments and lamellar granules are seen. The epidermis of 7th day group is made up of $7\sim8$ keratinocytes. Numerous KHGs are seen in granular layer cells. KHGs are located in granular layer cells as well as spinous layer cells. The epidermis of End week group is composed of one-layered basal cell and $1\sim2$ layered superficial cells. Various sized-KHGs are observed in granular layer cells. The results of the present study suggest that as the epidermis should be keratinized during proliferation and remodeling process, so keratinization of the epidermis would play a major role of wound healing process.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1658_1659
• /
• 2009

PLS(Pohang Light Source) will begin the PLS-II project that has been funded by the KOREA Government in order to further upgrade the PLS which has operated since 1992. The control system of the PLS-II has distributed control architecture, with two layers of hierarchy; operator interface computer (OIC) layer and machine interface computer (MIC) layer. The OIC layer is based on SUN workstation with UNIX. A number of PC-based consoles allow to remotely operating the machine from the control room. PC-based consoles use the Linux or Windows operation system. Similar consoles in the experimental hall are used to control experiments. The MIC layer is directly interfaced to individual machine devices for low-level data acquisition and control. MIC layer is based on VMEbus standard with vxWorks real-time operating system. Executable application software modules are downloaded from host computers at the system start-up time. The MIC's and host computers are linked through Ethernet network. It should enable the use of hardware and software already developed for specific light source requirements. The core of the EPICS (Experimental Physics and Industrial Control System)[1] has been chosen as the basis for the control system software.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.13 no.4
• /
• pp.675-683
• /
• 2009

RC6 which has different algorithm of encryption and decryption has been proposed to have the same algorithm between encryption and decryption through inserting symmetry layer using simple rotate and logical operation. That means the half of whole RC6 round uses encryption algorithm and the rest of it uses decryption one and symmetry layer has been put into the middle of encryption and decryption. The proposed RC6 algorithm has no difference with the original one in the speed of process. However it is quite safe because by inserting symmetry layer the path of high probability which is needed for differential and linear analysis is cut off so that it is hard to be analyzed. The proposed symmetry layer algorithm can be easily applied to the algorithm which has different encryption and decryption and make it same, and it can be good idea to be used to design a new block cipher algorithm.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.4
• /
• pp.264-269
• /
• 2016

This paper reports a fundamental study of temperature characteristics of a solar pond with an insulation layer. Further, these characteristics were compared with those of a solar pond without the insulation layer. The governing equation was discretized via finite difference method. The governing equations are two-dimensional unsteady-state second-order partial differential equations. The conclusions of the study are as follows: 1) If the depth of the solar pond was increased, the desired effect of increase in temperature was not produced because the amount of solar insolation received by the bottom of the solar pond decreased. 2) As the temperature of the soil during winter is higher than the temperature of the water in a solar pond, heat was transferred from the soil to the solar pond. 3) For the case of the solar pond with insulation layer, it was estimated that the dependence rate of solar energy was 83.3% and that of the boiler was 16.7%.