• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.333-338
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• 2017

Recently, because of the mobile device generalization tendency, a lot of new mobile applications which need mobile database on mobile devices appear. SQLite, Realm, etc. are representative mobile databases, and they are the database engines which are suitable for small devices that have large resource restriction and are used a lot in mobile devices based on Linux. These engines are open source programs and have advantages which are lighter weight and faster speed than general purpose databases. This paper focuses on the performance experiments and analysis of SQLite, which is front runner in mobile database fields. Considering the target mobile environments, the test is performed at Linux environment. And this paper implements performance test program and performs performance experiment of SQLite database to test search efficiency. The experiment is processed by comparison with the results of a Oracle database working out at the same environment.

• Journal of Biosystems Engineering
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• v.34 no.2
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• pp.114-119
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• 2009

Field test was conducted to investigate primary factors reducing rapeseed harvesting using a reciprocating cutter-bar of combine. The results showed that the correlation between crop moisture content and yield loss had a U-type, which indicated that the yield reduction increased at too high and too low crop moisture contents. The proper ranges of crop moisture contents were 27${\sim}$35%, 21${\sim}$56%, and 62${\sim}$73% in case of grain, pod and stem, respectively. Crop moisture content was negatively correlated with header loss, but positively correlated with threshing loss. In contrary, stem moisture content showed positive correlations with total loss, threshing loss and separation loss. Working speed was positively correlated with header loss. Total flow rate, pod flow rate and stem flow rate were highly correlated with threshing loss and separation loss. However, grain flow rate did not show any correlation with total loss. According to the principal component analysis, two principal components were derived as components with eigenvalues greater than 1.0. The contribution rates of the first and the second components were 52.7% and 38.9%, which accounted for 91.6% of total variance. As a contributive factor influencing total loss of rapeseed mechanical harvesting, a crop moisture content factor was greater than a crop flow rate factor. The stepwise multiple regression analysis for total loss was conducted using crop moisture content factor, crop flow rate factor and coefficient. However, the model did not show any correlation among independent and dependent factors ($R^2$=0.060).

• Journal of Astronomy and Space Sciences
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• v.32 no.1
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• pp.81-89
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• 2015

In this paper, we describe the development of a bioreactor for a cell-culture experiment on the International Space Station (ISS). The bioreactor is an experimental device for culturing mouse muscle cells in a microgravity environment. The purpose of the experiment was to assess the impact of microgravity on the muscles to address the possibility of long-term human residence in space. After investigation of previously developed bioreactors, and analysis of the requirements for microgravity cell culture experiments, a bioreactor design is herein proposed that is able to automatically culture 32 samples simultaneously. This reactor design is capable of automatic control of temperature, humidity, and culture-medium injection rate; and satisfies the interface requirements of the ISS. Since bioreactors are vulnerable to cell contamination, the medium-circulation modules were designed to be a completely replaceable, in order to reuse the bioreactor after each experiment. The bioreactor control system is designed to circulate culture media to 32 culture chambers at a maximum speed of 1 ml/min, to maintain the temperature of the reactor at $36{\pm}1^{\circ}C$, and to keep the relative humidity of the reactor above 70%. Because bubbles in the culture media negatively affect cell culture, a de-bubbler unit was provided to eliminate such bubbles. A working model of the reactor was built according to the new design, to verify its performance, and was used to perform a cell culture experiment that confirmed the feasibility of this device.

• Journal of the Korean Institute of Landscape Architecture
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• v.31 no.3
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• pp.91-106
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• 2003

The objective of this study is to present management methods for Korean golf courses to achieve fast green that satisfies international golf tournament standards during an official golf tournament. The results of both the research and the comparative study on putting green management of 24 tournaments hosted in Korea and 12 tournaments hosted in overseas countries in 2002 are as follows: 1. As for the putting greens in Korean and foreign golf courses where official golf tournaments were held, Korean of official golf tournaments were mainly opened in two-green system golf courses contrary to the foreign cases, and the average size of the greens in Korean golf courses was shown to be greater than that of foreign golf courses to some extent, although there was no difference between the types of turf varieties. 2. Results have shown that unlike foreign golf courses, Korean golf courses were managing putting greens by using greens mowers mostly for general (non-tournament) management, and elaborate rolling attempts failed during official tournament flay week because of an insufficient number of rollers to be input. Therefore, Korean golf courses are required to make efforts to secure 21-inch working-behind greens mowers equipped with tournament bedknifes and 11 blades, which is the greens mowing equipment for professional tournaments, and rollers above all things in order to achieve fast green during tournament play week 3. In attempting to achieve green as fast as that of foreign golf courses, Korean golf courses need to consider the method of performing mowing at 3.0mm height or less with greens mowers for professional tournaments. This needs to be done more than two times, followed by a continuous practice of rolling for proper management.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.331-336
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• 2006

The rail clamp is the device to prevent that a crane slips along rails due to the wind blast as well as to locate the crane in the set position for loading and unloading containers. The wedge type rail clamp should be designed to consider the structural instability and the durability because it compresses both rail side with large clamping force by the wedge working as the wind speed increases. In this research, there are two methods which are design of experiment and variation technology in used commercial software and shape optimization was performed. The optimum results obtained by the two methods are compared and examined.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1623-1629
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• 2015

By increasing due to large-scale residential and commercial apartments or factories or were, and increases the length of the cable is connected from the electrical room, the thickness of the cable, the trend is also being gradually thicker to increase the power consumption. In this paper, the programs install the cable inserted in the rope a double bonded brake pipe to be laid underground in these cables, and to reliably collect various kinds of data such as a tension at the time of laying the cable, the distance and speed design, and the sample data was acquired through hardware making them. Through this, it was confirmed that, worker was significantly reduced and work time was shortened to the traditional mechanical laying equipment. And to obtain a performance of improving the reliability of operation, because the use of the working data to the management and evaluation.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.263-269
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• 2010

This paper describes real-time detection and tracking of moving objects for unmanned visual surveillance. Using images obtained from the fixed camera it detects moving objects within the image and tracks them with displaying rectangle boxes enclosing the objects. Tracking method is implemented on an embedded system which consists of TI DSK645.5 kit and the FPGA board connected on the DSP kit. The DSP kit processes image processing algorithms for detection and tracking of moving objects. The FPGA board designed for image acquisition and display reads the image line-by-line and sends the image data to DSP processor, and also sends the processed data to VGA monitor by DMA data transfer. Experimental results show that the tracking of moving objects is working satisfactorily. The tracking speed is 30 frames/sec with 320x240 image resolution.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.356-356
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• 2010

Tribological behaviors of the hard film on soft substrate system were explored using the hard thin film of diamond-like carbon (DLC) coated the soft polymer of polydimethysiloxane (PDMS). A DLC film with the Young's modulus of 100 GPa was coated on PDMS substrate with Young's modulus of 10 MPa using plasma enhanced chemical vapor deposition (PECVD) technique. The deposition time was varied from 10 sec to 10 min, resulting in nanoscale roughness of wrinkle patterns with the thickness of 20 nm to 510 nm, respectively, at a bias voltage of $400\;V_b$, working pressure 10 mTorr. Nanoscale wrinkle patterns with 20-100 nm in width and 10-30 nm height were formed on DLC coating due to the residual stress in compression and difference in Young's modulus. Nanoscale roughness effect on tribological behaviors was observed by performing a tribo-experiment using the ball-on-disk type tribometer with a steel ball of 6 mm in diameter at the sliding speed of 220 rpm, normal load of 1N and 25% humidity at ambient temperature of $25^{\circ}C$. Friction force were measured with respect to thickness change of coated DLC thin film on PDMS. It was found that with increases the thickness of DLC coating on PDMS, the coefficient of friction decreased by comparison to that of the uncoated PDMS. The wear tracks before and after tribo-test were analyzed using SEM and AFM.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.3
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• pp.30-37
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• 2004

This thesis develops a fuzzy-PID control algorithm for control the filament winding tension. It is developed by applying classical PID control technique to a fuzzy logic controller. It is composed of a fuzzy-PI controller and a fuzzy-D controller. The fuzzy-PI controller uses error and integrated error as inputs, and the fuzzy-D controller uses derivative of error as input. The fuzzy-PI controller uses Takagi-Sugeno fuzzy inference system, and the fuzzy-D controller uses Mamdani fuzzy inference system. The fuzzy rule base for the fuzzy-PI controller is designed using 19 rules, and the fuzzy rule base for the fuzzy-D controller is designed using 5 rules. A test-bed is set-up for verifying the effectiveness of the developing control algorithm in control the filament winding tension. It is composed of a mandrel, a carriage, a force sensor, a driving roller, nip rollers, a creel, and a real-time control system. Nip rollers apply a vertical force to a filament, and the driving roller drives it. The real-time control system is developed by using MATLAB/xPC Target. First, experiments for showing the inherent problems of an open-loop control scheme in a filament winding are performed. Then, experiments for showing the robustness of the developing fuzzy-PID control algorithm are performed under various working conditions occurring in a filament winding such as mandrel rotating speed change, carriage traversing, spool radius change, and reference input change.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2031-2038
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• 2008

A small-area and high-speed authentication/security processor (WUSB_Sec) IP is designed, which performs the 4-way handshake protocol for authentication between host and device, and data encryption/decryption of wireless USB system. The PRF-256 and PRF-64 are implemented by CCM (Counter mode with CBC-MAC) operation, and the CCM is designed with two AES (Advanced Encryption Standard) encryption coles working concurrently for parallel processing of CBC mode and CTR mode operations. The AES core that is an essential block of the WUSB_Sec processor is designed by applying composite field arithmetic on AF$(((2^2)^2)^2)$. Also, S-Box sharing between SubByte block and key scheduler block reduces the gate count by 10%. The designed WUSB_Sec processor has 25,000 gates and the estimated throughput rate is about 480Mbps at 120MHz clock frequency.