• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2006.05a
• /
• pp.391-394
• /
• 2006

This paper presents soft switching zero voltage switching high frequency inverter for rare gas fluorescent lamp using dielectric-barrier discharge phenomenon. The simple high-frequency inverter can completely achieve stable zero voltage soft switching (ZVS) commutation for wide its output power regulation ranges and load variations under its constant high frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally described and discussed for a constant high-frequency PDM control strategy under a stable ZVS operation commutation, together with its output effective power regulation characteristics-based on the high frequency PDM strategy. The experimental operating performances of this high frequency Inverter are illustrated as compared with computer simulation results and experimental ones. Its light dimming characteristics due to power regulation scheme are evaluated and discussed on the basis of simulation and experimental results. The feasible effectiveness of this high frequency inverter appliance implemented here is proven from the practical point of view.

• Proceedings of the IEEK Conference
• /
• 2004.06b
• /
• pp.343-346
• /
• 2004

This paper proposes a leakage-suppressed SRAM with dynamic power saying scheme for the future leakage-dominant sub-70-nm technology. By dynamically controlling the common source-line voltage ($V_{SL}$) of sleep cells, the sub-threshold leakage through these sleep cells can be reduced to be 1/10-1/100 due to the reverse body-bias effect, dram-induced barrier lowering (DIBL) and negative $V_{GS}$ effects. Moreover, the bit-ling leakage which mar introduce a fault during the read operation can be completely eliminated in this new SRAM. The dynamic $V_{SL}$ control can also reduce the bit-line swing during the write so that the dynamic power in write can be reduced. This new SRAM was fabricated in 0.35-${\mu}m$ CMOS process and more than $30\%$ of dynamic power saying is experimentally verified in the measurement. The leakage suppression scheme is expected to be able to reduce more than $90\%$ of total SRAM power in the future leakage-dominant 70-nm process.

• Archives of design research
• /
• v.12 no.3
• /
• pp.29-40
• /
• 1999

Walter Gropius, famous architect of Bauhaus, once treated of pure mind which was revealed in the system of object and its phenomena through sense of sight while examining material being and illusive being. And Thomas Aquinas said that man can have a creative power only with modest mental state void of prejudice saying that he expected God to come to him after his soul went out of him. The same thing was said by so many great philosophers and thinkers other than him. I think his saying, "God comes after Soul's escape from the body for a new creation", has a real truth for all times and places and beauty itself beyond expression. Why\ulcorner The reason why the saying is so true is because it has a Yin and Yang Idea, that is, the Soul means a dark spirit correspondent to Yin between both oriental ideas and God does a bright spirit correspondent to Yang between them. By reason of this idea, I would like to assert that we should take it granted that we stand in need of the same bright Yang's spirit as God has for the new creation, and let the Yang's bright spirit come to our minds. We can call it divine 'Providence', or call it God's guidance, which we cannot help accepting as a man's fatality. As God was pleased after he made man and all the creatures by dint of his design, so man was pleased after he made everything he needed by the same design that he accepted from God. In spite of pleasure of different dimensions from what God and Man has each other, their way of empathies were all the same. In this paper I compared a worldly lower conception by which man designed his products for his sensuous satisfaction with a higher conception by which God designed his creatures for his mental satisfaction. I intended to infer what destined relation there must be between both God's and man's creations, trying to remind designers that they have to confess to have not so divine a providence as God has for creation because I think the real truth is that they had regarded their works of product design as a routine occurrence for their physical convenience in the industrial plans.ial plans.

• Proceedings of the KIEE Conference
• /
• 2001.07e
• /
• pp.67-71
• /
• 2001

Nowdays, we can communicate using Information Technology such as internet, personal computer, mobile phone etc. To protect global environment, it is also reqired to invent products efficiently reduce energy consumption. here, I studied organic EL and inorganic EL because organic EL display is appropriate device as light, thin, energy-saying display following CRT, LCD. As a result, I realized that we are supposed to study more on invention, efficiency and mass-production of materials. Comparing with another display, however, it would be marketable in few years, considering short history of its full-scaled studies.

• Speech Sciences
• /
• v.8 no.4
• /
• pp.185-191
• /
• 2001

This study was designed to determine what components of spoken language have been relatively neglected in the teaching of listening comprehension in Korea and to suggest a model of listening process. Two types of tests were undertaken using spoken and written forms of English with secondary school teachers of English and college students. Findings: Hearing power has been generally neglected in the teaching of listening comprehension. Hearing power which can be thought as an active process is defined as an ability to transfer the sequence of discrete phonetic segments without word boundary into the sequence of words in phonemic representations by using both nonlinguistic factors and linguistic factors including perception rules based on phonetics and phonology. Vocabularies, hearing-speaking power, syntactic structures and idiomatic expressions are to be taught for spoken English. A model of listening process was suggested and discussed.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.10 no.9
• /
• pp.1679-1684
• /
• 2006

DVB-H(Digital Video Broadcasting for Handhold) is a new standard, currently being developed, which defines mobile enhancements for the DVB-T (DVB-Terrestrial) standard. For the reception of service via mobile handheld devices, seamless mobility and power saving are essential requirements of DVB-H. For seamless handover, the receiver should monitor neighboring cells and it increases the power consumption. And so, power efficient handover scheme to support both mobility and power saving is required. In this paper, we propose power efficient handover scheme to reduce power consumption by reducing the number of frequency scanning during the handover. Through the numerical evaluation, we analyze the performance of handover schemes.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.42 no.1
• /
• pp.95-100
• /
• 2005

This paper proposes a DVS method which effectively reduces the power consumption of multimedia signal processor. Analytic derivations of effective range of its power saving factor are obtained with the assumption of a Gaussian distribution for the frame-based computational burden of the multimedia processor. A closed form equation of the power saving factor is derived in terms of the mean-standard deviation of the distribution. An MPEG-2 video decoder algorithm and AAC encoder algorithm are tested on ARM9 RISC processor for the experimental verification of the power saying of the proposed DVS approach. The experimental results with diverse MPEG-2 video and audio files show 50～30% power saving factor and show good agreement with those of the analytically derived values.

• Proceedings of the KIPE Conference
• /
• 2004.07b
• /
• pp.851-854
• /
• 2004

This paper studies Optical Fiber(OF) - LED illuminated display board system for energy saving. The OF-LED illuminated display board system has PV modules, batteries, and charge & discharge system, and dynamic full color display controller. Both maximum power point tracker (MPPT) and constant current & constant current controls (CCVC) are used In govern the charging system. It can be improve the charging efficiency of battery. The objective of this thesis paper is to build advertisement lighting system with OF-LED in to charge a 12-volts lead acid battery by using a field wired PV array. We saved the maintenance cost and developed of advertisement effectiveness. To verify the proposed OF-LED illuminated display board system for energy saving, the detail simulation and experiment results indicate that operating characteristics are verified by experiment with a laboratory prototype in this paper.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.1281-1283
• /
• 2001

An investigation into power conditioners that interface with photovoltaic array and utilities has been completed. The rating for this investigation is residential system(3-5kW) that interface with a 220V single phase utility connection. As the result of this investigation, a 3kW high frequency PWM IGBT inverter feeding a high frequency isolation transformer with a sinusoidal current wave was selected. The output of the transformer rectified with a diode bridge rectifier four IGBT, used as 60Hz switched, reverse the polarity of the rectified current on every other half cycle of the utility voltage. Even though the high frequency link system used more power semiconductors a net size, weight, and parts cost saying result compared to the other systems due to elimination of 60Hz transformer.

• The KIPS Transactions:PartC
• /
• v.11C no.4
• /
• pp.555-562
• /
• 2004

We consider differentiated bandwidth allocation for a piconet in short-range wireless personal network systems : Bluetooth. Since bandwidth requirements nay vary among applications/services, and/or it may change over time, it is important to decide how to allocate limited resources to various service classes to meet their service requirements. We propose a simple and efficient bandwidth allocation mechanism which meets bandwidth requirements of various service types while saving power consumption by a Power saying mode, i.e., sniff node. We compare our proposed mechanism with a conventional (weighted) round-robin polling scheme and show that it achieves significant improvement of hroughput, delay, and power consumption.