• Journal of IKEEE
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• v.22 no.4
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• pp.1088-1092
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• 2018

In this paper, we propose a dual-mode frequency tripler using push-push and stacked FET structures. The proposed circuit can operate either in frequency multiplier mode or in amplifier mode. In the frequency multiplier mode, push-push frequency multiplication is achieved by allowing input signals with particular phase shifts. In the amplifier mode, the device operates as a distributed amplifier to obtain high gain. Also both modes were designed using stacked FET structure. The designed circuit showed frequency tripled output power of 9.7 dBm at 2.4 GHz with the input at 800 MHz. On the other hand, in the amplifier mode, the device showed 8.9 dB of gain to generate 19.5 dBm at 800 MHz.

• Journal of Navigation and Port Research
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• v.35 no.2
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• pp.113-119
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• 2011

This paper is a part of the development on the safe navigation model of tugs and barges in Korea waters. desk-top tug-barge simulator is to train the crew of tugs and barges, especially tugs' crew. It is connected with steering and engine telegraph console and winch control console, and can describe three types of operation mode for a tug-barge working unit, towing mode, side by side and push mode. It can also record and assess each simulation run. The evaluation module can confirm the result of a finished simulation run and help trainees to find and correct their faults, and it is composed of result evaluation and process evaluation.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.339-342
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• 1988

Typical magnetic bubble propagation failure modes of ion implanted magnetic bubble computer memory devices were observed and their failure mechanisms were analize. The skidding failure mode is due to the pushing of a strong repulsive charged wall. If this pushing is stronger than the edge affinity of the bubble in the cusp, the bubble moves out of the cusp when it is supposed to stay there. The stripeout failure modes across the adjacent track or along the track can be explained by considering the relative strength of the charged wall and the edge affinity encountered by both ends of the stripe. The skipping of the first cusp of a track is believed to be due to the whipping motion of the charged wall. The bubble moves directly to the second cusp via the long charged wall pointing to the second cusp skipping the first cusp.

• Journal of ILASS-Korea
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• v.18 no.3
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• pp.132-139
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• 2013

Smoke emissions from light duty diesel vehicles were measured using light extinction method with the free acceleration test mode. The smoke emissions for each measurement cycle of the free acceleration method showed large variations according to driver's pedal pushing pattern. The smoke values for each measurement cycle initially increased and reach a peak value. Integration of the smoke emissions with time for each measurement cycle was performed to get a representative smoke value which was obtained by averaging the integrated results. Two kinds of integration time range were used. One is range over the whole measurement cycle of the free acceleration method. The other is only the acceleration range in the measurement cycle. Overall, variation of the representative smoke values obtained by the integration method was reduced comparing to the traditional representative smoke value which was obtained from a peak smoke value over the measurement cycle. Ten vehicles of the same model with 2.5 liter diesel engines, and seven vehicles of the same model with 2.7 liter diesel engines, were tested using the free acceleration test method.

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.1-8
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• 2012

Characteristics of smoke emission in light duty diesel vehicles was investigated according to the year of production, engine displacement volume, and mileage. The smoke emission was measured using light extinction smoke measurement method under free acceleration test mode. Total number of the tested vehicles was 180. The year of production of the tested vehicles distributed from 2002 to 2007. The displacement volumes of the tested vehicles were categorized as 2-liter, 2.5-liter, 2.7-liter, and 3-liter. The mileage of the tested vehicles distributed from 20,000 km to 400,000 km. The more recent in the year of production of the tested vehicles did not show clearly lower in smoke emissions. Smoke emission showed different values according to driver's pedal pushing pattern. Also, smoke emission peak for each free acceleration test initially increased and reach a maximum of the peak values. Afterwards, the smoke peak gradually decreased as number of test increased. A new guide line was proposed to determine the smoke value from the light duty diesel vehicles based on smoke emission peak patterns which were obtained with several repeated free acceleration tests.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1542-1546
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• 2003

Nanotechnology is an important challenge, for which nanoparticle manipulation plays an important role in the assembly of nano elements. In this study, the dynamic equation of system plant is established by van der Waals force, friction, capillary forces etc. To push nanoparticles, strain gauges are used as sensors to actuate an X-Y stage in an atomic force microscopy system. A strategy of pushing nanoparticles is developed based on sliding mode control. Moreover, afuzzy controller is responsible for compensating tip-particle contact loss according to feedback signals of a laser-detector system. According to position control result, experimental results of gold nanoparticle manipulation are presented.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.66-71
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• 2008

The data of the deformation and the stress according to time are studied at upper model of press and lower model of the blanking plate applied by press with the width, length and height of 0.4 m and 0.6 m respectively. The press is pushing downward on the plate fixed at the lower floor. These data are compared and investigated through this study. By using these results, there is the maximum deformation at 4 corners in the lower plate model of aluminium alloy fixed at lower floor. This deformation incase of elapsed time of 0.6 second becomes 4 times as much as in case of elapsed time of 0.2 second. The quantity of deformation at the lower plate model becomes more than at the upper press model to the extent of 10%. At the lower plate model of aluminium alloy, there is the maximum Von-Mises equivalent stress at 4 corners and both sides of middle area on the lower plate model of aluminium alloy. This stress in case of elapsed time of 0.6 second becomes 6 times as much as in case of elapsed time of 0.2 second. The Von-Mises equivalent stress of lower plate model becomes 2 times as much as that of upper press mode.

• Journal of Communications and Networks
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• v.4 no.2
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• pp.128-135
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• 2002

We propose a new space priority mechanism, and analyze its performance in a single Constant Bit Rate (CBR) server. The arrival process is derived from the superposition of two types of traffics, each in turn results from the superposition of homogeneous ON-OFF sources that can be approximated by means of a two-state Markov Modulated Poisson Process (MMPP). The buffer mechanism enables the Asynchronous Transfer Mode (ATM) layer to adapt the quality of the cell transfer to the Quality of Service (QoS) requirements and to improve the utilization of network resources. This is achieved by "Selective-Delaying and Pushing-ln"(SDPI) cells according to the class they belong to. The scheme is applicable to schedule delay-tolerant non-real time traffic and delay-sensitive real time traffic. Analytical expressions for various performance parameters and numerical results are obtained. Simulation results in term of cell loss probability conform with our numerical analysis.

• World Technopolis Review
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• v.1 no.4
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• pp.276-286
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• 2013

"Federal investments into the future of a region" - pushing economy in the right direction or throwing tax money into a black hole? Hot-headed contentions keep circulating within politics and economy discussing the effect of technology centers and their sustainability within a region. Start-up support and technological infrastructure with the auxiliary service of well developed sector-oriented clusters as a fertile soil for successful networks are an undeniable advantage of well organised technology centers. Sceptic contemporaries still hold against that in order to implement such a center millions of federal funds for infrastructure and operation are invested. What output of this tax money is verifiable in the long run? The case of Dortmund provides substantial food for this necessary and relevant discussion. Now, after 27 years of history of the TechnologieZentrumDortmund, TZDO for short, a positive balance can be drawn. This is not just a matter of personal belief and stance. Fortunately, a recent study on the economic effects of the TZDO on the whole region was performed by the Center of Applied Economy Research M$\ddot{u}$nster, Germany (Gundel and Luttmann 2008). The result is clear and measurable: the TZDO has shown to be of great impact on the positive development of a whole region. This paper presents an account of the approach of the TechnologieZentrumDortmund and its current strategy and mode of operation to reach an utmost of effectiveness of personal and pecuniary input in establishing economic success for the region of Dortmund. An immense change of minds, employment opportunities and a massive structural change of the whole region were some of the ambitious aims that had to be reached and that are achieved to a large extent.

• Korean Journal of Materials Research
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• v.34 no.1
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• pp.34-43
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• 2024

New piezoelectric and triboelectric materials for energy harvesting are being widely researched to reduce their processing cost and complexity and to improve their energy conversion efficiency. In this study, BaTiO₃ films of various thickness were deposited on Ni foams by R.F. magnetron sputtering to study the piezoelectric and triboelectric properties of the porous spongy structure materials. Then piezoelectric nanogenerators (PENGs) were prepared with spongy structured BaTiO₃ and PDMS composite. The output performance exhibited a positive dependence on the thickness of the BaTiO₃ film, pushing load, and poling. The PENG output voltage and current were 4.4 V and 0.453 ㎂ at an applied stress of 120 N when poled with a 300 kV/cm electric field. The electrical properties of the fabricated PENG were stable even after 5,000 cycles of durability testing. The triboelectric nanogenerators (TENGs) were fabricated using spongy structured BaTiO₃ and various polymer films as dielectrics and operated in a vertical contact separation mode. The maximum peak to peak voltage and current of the composite film-based triboelectric nanogenerator were 63.2 V and 6 ㎂, respectively. This study offers new insights into the design and fabrication of high output nanogenerators using spongy structured materials.