Yongseok Choi

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—Most digital systems are equipped with dc–dc converters to supply various levels of voltages from batteries to logic devices. DC–DC converters maintain legal voltage ranges regardless of the load current variation as well as battery voltage drop. Although the efficiency of dc–dc converters is changed by the output voltage level and the load current, most(More)
In this paper, we introduce a precise energy characterization of SDRAM main memory systems and explore the amount of energy associated with design parameters, leading to energy reduction techniques that we are able to recommend for practical use.We build an in-house energy simulator for SDRAM main memory systems based on cycle-accurate energy measurement(More)
ALONG WITH SPEED AND COST, energy consumption is now a primary performance metric for battery-operated embedded systems. A well-designed embedded system should be globally optimized to the target application , from the user interface to the device technology. This type of global optimization over many layers of software and hardware is challenging because(More)
Memory systems are dominant energy consumers, and thus many energy reduction techniques for memory buses and devices have been proposed. For practical energy reduction practices, we have to take into account the interaction between a processor and cache memories together with application programs. Furthermore, energy characterization of memory systems must(More)
Most digital systems are equipped with DC-DC converters to supply various levels of voltages from batteries to logic devices. DCDC converters maintain legal voltage ranges regardless of the load current variation as well as battery voltage drop. Although the efficiency of DC-DC converters is changed by the output voltage level and the load current, most(More)
NAND flash memory can provide cost-effective secondary storage in mobile embedded systems, but its lack of a random access capability means that code shadowing is generally required, taking up extra RAM space. Demand paging with NAND flash memory has recently been proposed as an alternative which requires less RAM. This scheme is even more attractive for(More)
A new feature set suited for IP telephony is described. The user value of this feature set is discussed in terms of social science results. This feature set supports natural human collaboration within a human environment. The use by humans of casual awareness to support collaboration is discussed and models taken from architectural research are used to show(More)
—New fusion memory devices consisting of multiple heterogeneous memory components in a single die or package offer efficient ways to optimize embedded systems in terms of energy, performance, and cost. Samsung Electronics recently announced the OneNAND fusion memory, in which a NAND flash array is integrated with dual SRAM buffers to provide a NOR-type I/O(More)