Ha-young Jeong

Scalable distributed memory embedded system with a low-cost hardware message passing interface

In this paper, we propose a scalable distributed memory system with a low-cost hardware message-passing interface. The proposed interface improves the communication performance between nodes to decrease the overhead synchronization with a receiver reservation technique. The simulation results indicate that the performance is increased by 20% on 4x4 communications. The synthesis result of the proposed MPI indicates that the area was only 4.49% of each computing node. As a result, the proposed system is a useful embedded MPSoCs (Multiprocessor System on a Chip) for its low-cost implementation and scalability.

Optical dispersion control in surfactant-free DNA thin films by Vitamin B2 doping

A new route to systematically control the optical dispersion properties of surfactant-free deoxyribonucleic acid (DNA) thin solid films was developed by doping them with vitamin B2, also known as riboflavin. Surfactant-free DNA solid films of high optical quality were successfully deposited on various types of substrates by spin coating of aqueous solutions without additional chemical processes, with thicknesses ranging from 18 to 100 nm. Optical properties of the DNA films were investigated by measuring UV-visible-NIR transmission, and their refractive indices were measured using variable-angle spectroscopic ellipsometry. By doping DNA solid films with riboflavin, the refractive index was consistently increased with an index difference Δn ≥ 0.015 in the spectral range from 500 to 900 nm, which is sufficiently large to make an all-DNA optical waveguide. Detailed correlation between the optical dispersion and riboflavin concentration was experimentally investigated and thermo-optic coefficients of the DNA-riboflavin thin solid films were also experimentally measured in the temperature range from 20 to 85 °C, opening the potential to new bio-thermal sensing applications.

Irreversible denaturation of DNA: a method to precisely control the optical and thermo-optic properties of DNA thin solid films

The denaturation of double-stranded deoxyribonucleic acid (ds-DNA) has been well known to break nucleobase bonds, resulting in single-stranded deoxyribonucleic acid (ss-DNA) in solutions, which can recombine to form ds-DNA in a reversible manner. We developed an efficient process to irreversibly maintain various DNA denaturation levels in thin solid films in order to investigate the impacts of the denaturation on the optical properties of DNA films. By adding NaOH in an aqueous solution of salmon testis DNA, we flexibly controlled the level of denaturation in the solution, which was then spin-coated on Si and silica substrates to irreversibly bind ss-DNAs in a thin solid film. The denaturation of DNA in thin solid films was experimentally confirmed by ultraviolet-visible and Fourier transform infrared spectroscopic investigations, whose level could be controlled by the NaOH content in the aqueous solution precursor. By this irreversible denaturation process, we developed a new method to flexibly vary the refractive index of DNA thin solid films in a wide range of Δn>0.02 in the visible to near-infrared range. Thermo-optic coefficients dn/dT of the films were also experimentally measured in the temperature range from 40°C to 90°C to confirm the significant impacts of denaturation. Detailed thin film processes and optical characterizations are discussed.

The Design of Hardware MPI Units for MPSoC

In this paper, we propose a novel hardware MPI(Message Passing Interface) unit which supports message passing in multiprocessor system which use distributed memory architecture. MPI Hardware unit processes data synchronization, transmission and completion, and it supports processor non-blocking operation so it reduces overhead according to synchronization. Additionally, MPI hardware unit combines ready entry, request entry, reserve entry which save and manage the synchronized messages and performs the multiple outstanding issue and out of order completion. According to BFM(Bus Functional Model) simulation result, the performance is increased by 25% on many to many communication. After we designed MPI unit using HDL, with synopsys design compiler we synthesized, and for synthesis library we used MagnaChip . And then we making prototype chip. The proposed message transmission interface hardware shows high performance for its increase in size. Thus, as we consider low-cost design and scalability, MPI hardware unit is useful in increasing overall performance of embedded MPSoC(Multi-Processor System-on-Chip).

A Partial Access Mechanism on a Register for Low-Cost Embedded Multimedia ASIP

In this letter, we propose a partial access mechanism to be used on a register file for low-cost embedded multimedia processor architecture. In the embedded system, supporting the SIMD operations is a burden because of the wide SIMD register file and its execution unit. So a new architecture is proposed to increase the performance of SIMD operations with minimal additional hardware overhead. To evaluate the performance and hardware overhead, this architecture is adopted to an embedded multimedia processor and simulated with five DSP benchmarks. The simulation results indicate that the performance is increased by 38% and the total area is increased by 13.4%. The proposed partial access mechanism may be useful for low-cost embedded multimedia ASIP.