• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.5
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• pp.38-47
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• 1999

We have designed a 16bit adder which reduces the power consumption at each level of architecture, logic and transistor. The conventional ELM adder has a major disadvantage which makes glitch in the G cell when the particular input bit patterns are applied, because of the block carry generation signal computed by the input bit pattern. Thus, we propose a low power adder architecture which can automatically transfer each block carry generation signal to the G cell of the last level to avoid glitches for particular input bit patterns at the architecture level. We also use a combination of logic styles which is suitable for low power consumption with static CMOS and low power XOR gate at the logic level. Futhermore, The variable-sized cells are used for reduction of power consumption according to the logic depth of the bit propagation at the transistor level. As a result of HSPICE simulation with $0.6\mu\textrm{m}$ single-poly triple-metal LG CMOS standard process parameter, the proposed adder is superior to the conventional ELM architecture with fixed-sized cell and fully static CMOS by 23.6% in power consumption, 22.6% in power-delay-product, respectively.

• Progress in Superconductivity
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• v.6 no.1
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• pp.7-12
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• 2004

Due to the very fast switching speed of Josephson junctions, superconductive digital circuit has been a very good candidate fur future electronic devices. High-speed and Low-power microprocessor can be developed with Josephson junctions. As a part of an effort to develop superconductive microprocessor, we have designed an RSFQ 4-bit ALU (Arithmetic Logic Unit) in a pipelined structure. To make the circuit work faster, we used a forward clocking scheme. This required a careful design of timing between clock and data pulses in ALU. The RSFQ 1-bit block of ALU used in this work consisted of three DC current driven SFQ switches and a half-adder. We successfully tested the half adder cell at clock frequency up to 20 GHz. The switches were commutating output ports of the half adder to produce AND, OR, XOR, or ADD functions. For a high-speed test, we attached switches at the input ports to control the high-speed input data by low-frequency pattern generators. The output in this measurement was an eye-diagram. Using this setup, 1-bit block of ALU was successfully tested up to 40 GHz. An RSFQ 4-bit ALU was fabricated and tested. The circuit worked at 5 GHz. The circuit size of the 4-bit ALU was 3 mm ${\times}$ 1.5 mm, fitting in a 5 mm ${\times}$ 5 mm chip.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2039-2044
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• 2008

The problem of an efficient hardware implementation of multiple constant multiplication is frequently encountered in many digital signal processing applications such as FIR filter and linear transform (e.g., DCT and FFT). It is known that efficient solutions based on common subexpression elimination (CSE) algorithm can yield significant improvements with respect to the area and power consumption. In this paper, we present an efficient specialized adder design method for two common subexpressions ($10{\bar{1}}$, 101) in canonic signed digit (CSD) coefficients. By Synopsys simulations of a radix-24 FFT example, it is shown that the proposed method leads to about 21%, 11% and 12% reduction in the area, propagation delay time and power consumption compared with the conventional methods, respectively.

• Journal of the Korean association of regional geographers
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• v.3 no.2
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• pp.37-87
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• 1997

As a results of researches on the cultivation processes and settlement developments on the Mangyoung river valley as a whole could be have four 'Space-Time Continuity' through a [Origin-Destination] theory model. On a initial phases of cultivation, the cultivation process has been begun at mountain slopes and tributory plains in upper part of river-basin from Koryo Dynasty to early Chosun Dynasty. At first, indigenous peasants burned forests on the mountain slopes for making 'dryfield' for a cereal crops. Following population increase more stable food supply is necessary facets of life inducing a change production method into a 'wetfield' in tributory plains matching the population increase. First sedentary agriculture maybe initiated at this mountain slopes and tributory plains on upper part of river basin through a burning cultivation methods. Mountain slopes and tributory plains are become a Origin area in cultivation processes. It expanded from up to down through the valleys with 'a bits of land' fashion in a steady pace like a terraced fields expanded with bit by bit of land to downward. They expanded their land to the middle part of river basin in mid period of Chosun Dynasty with dike construction techniques on the river bank. Lower part of river cultivated with embankment building techniques in 1920s and then naturally expanded to the tidal marshes on the estuaries and river inlets of coastal areas. 'Pioneer fringes' are consolidated at there in modern times. Changes in landscapes are appeared it's own characters with each periods of time. Followings are results of study through the Mangyoung river valley as a whole. (1) Mountain slopes and tributory plains on the upper part of river are cultivated 'dryfields' by indigenous peasants with Burning cultivation methods at first and developed sedentary settlements at the edges of mountain slopes and on the river terrace near the fields. They formed a kind of 'periphery-located cluster type' of settlement. This type of settlement are become a prominant type in upper part of river basin. 'Dryfields' has been changed into a 'wetfields' at the narrow tributory plains by increasing population pressure in later time. These wetfields are supplied water by Weir and Ponds Irrigation System(제언수리방법). Streams on the tributory plains has been attracted wetfields besides of it and formed a [water+land] complex on it. 'Wetfields' are expanded from up to downward with a terraced land pattern(adder like pattern, 붕전) according to the gradient of valley. These periphery located settlements are formed a intimate ecological linkage with several sets of surroundings. Inner villages are expanded to Outer villages according to the expansion of arable lands into downward. (2) Mountain slopes and tributory plains expanded its territory to the alluvial deposited plains on the middle part of river valley with a urgent need of new land by population increase. This part of alluvial plains are cultivated mainly in mid period of Chosun Dynasty. Irrigation methods are changed into a Dike Construction Irrigation method(천방수리방법) for the control of floods. It has a trend to change the subjectives of cultivation from community-oriented one who constructed Bochang along tributories making rice paddies to local government authorities who could be gather large sums of capitals, techniques and labours for the big dike construction affairs. Settlements are advanced in the midst of plains avoiding friction of distances and formed a 'Centrallocated cluster type' of settlements. There occured a hierarchical structures of settlements in ranks and sizes according merits of water supply and transportation convenience at the broad plains. Big towns are developed at there. It strengthened a more prominant [water+land] complex along the canals. Ecological linkages between settlements and surroundings are shaded out into a tiny one in this area. (3) It is very necessary to get a modern technology of flood control at the rivers that have a large volume of water and broad width. The alluvial plains are remained in a wilderness phase until a technical level reached a large artificial levee construction ability that could protect the arable land from flood. Until that time on most of alluvial land at the lower part of river are remained a wilderness of overgrown with reeds in lacks of techniques to build a large-scale artificial levee along the riverbank. Cultivation processes are progressed in a large scale one by Japanese agricultural companies with [River Rennovation Project] of central government in 1920s. Large scale artificial levees are constructed along the riverbank. Subjectives of cultivation are changed from Korean peasants to Japanese agricultural companies and Korean peasants fell down as a tenant in a colonial situation of that time in Korea. They could not have any voices in planning of spatial structure and decreased their role in planning. Newly cultivated lands are reflected company's intensions, objectives and perspectives for achieving their goals for the sake of colonial power. Newly cultivated lands are planned into a regular Rectangular Block settings of rice paddies and implanted a large scale Bureaucratic-oriented Irrigation System on the cultivated plains. Every settlements are located in the midst of rice paddies with a Central located Cluster type of settlements. [water+land] complex along the canal system are more strengthened. Cultivated space has a characters of [I-IT] landscapes. (4) Artificial levees are connected into a coastal emnankment for a reclamation of broad tidal marshes on the estuaries and inlets of rivers in the colonial times. Subjectives of reclamation are enlarged into a big agricultural companies that could be acted a role as a big cultivator. After that time on most of reclamation project of tidal marshes are controlled by these agricultural companies formed by mostly Japanese capitalists. Reclaimed lands on the estuaries and river inlets are under hands of agricultural companies and all the spatial structures are formed by their intensions, objectives and perspectives. They constructed a Unit Farming Area for the sake of companies. Spatial structures are planned in a regular one with broad arable land for the rice production of rectangular blocks, regular canal systems and tank reservoir for the irrigation water supply into reclaimed lands. There developed a 'Central-located linear type' of settlements in midst of reclaimed land. These settlements are settled in a detail program upon this newly reclaimed land at once with a master plan and they have planned patterns in their distribution, building materials, location, and form. Ecological linkage between Newly settled settlemrnts and its surroundings are lost its colours and became a more artificial one by human-centred environment. [I-IT] landscapes are become more prominant. This region is a destination area of [Origin-Destination] theory model and formed a 'Pioneer Fringe'. It is a kind of pioneer front that could advance or retreat discontinously by physical conditions and socio-cultural conditions of that region.