Woo-young Choi

Quantitative Analysis of White Matter on DTI Images of Patients with Tinnitus: Preliminary Report

Tinnitus is defined as an unwanted auditory perception of internal origin, usually localized, and rarely heard by others. Persisting appearances of tinnitus are most commonly combined with diseases or damage in the inner ear or neuro-auditory pathway. Diffusion tensor magnetic resonance imaging (DTI) is a new imaging method with the capability of providing non-invasive information on tissue microstructure not available in routine clinical MRI images. Since white matter regions of the brain are an ordered structure due to the myelination and directionality of axons and have a high degree of anisotropy, the ability to detect changes in anisotropy can be extremely useful in the study of diseases such as tinnitus and multiple sclerosis, which are assumed to involve the demyelination of axons. While several studies investigated tinnitus using MRI, few studies tried to analyze neurological disorders quantitatively using DTI. In this study, the cerebral volume of white matter on DTI images of patients with tinnitus was measured using the semi-automated and intuitive menu based image processing tool (Human Analyzer, ETRI, Korea). Total number of ten patients with tinnitus including three women was examined

Providing flexible redundancy for an ATM access switch system

ATM switches require stringent reliability and availability even for access nodes. Carrier class ATM switches fulfill this requirement by employing expensive and sophisticated fault tolerant architectures. However, access switch systems are relatively cheap and compact. Most access switches support fundamental system reliability by providing redundancy for common parts of a system (e.g., switch fabric, power etc.). In addition to providing reliable connection to the core switch systems, access switch systems also need to support various customer premises services. Depending on the need of the network provider, highly reliable line redundancy is more important than the switching capacity of the access system or vice versa. This paper presents an implementation of an ATM switch that provides flexible line card redundancy and scalable switching capacity. Switching capacity of the system is scalable up to 10 Gbps from 5 Gbps depending on the configuration of line card redundancy.

Redundant multiprocessor interconnects for the high capacitor router built on ATCA

This paper is about multiprocessor interconnects for the high capacity router built on ATCA (advanced telecom computing architecture) platform. Multiprocessor inter-connection in ATCA brings some design issues when it comes to satisfy the constraint and specification of ATCA platform. In the multiprocessor communication, most transfers are from one port to the other ports or the opposite direction (usually between a main processor and local processors on line cards). Congestion may happen when inter-processor communication packets from local processors are simultaneously heading for a main processor. In order to manage or alleviate the congestion, bandwidth for inter-processor communication should be increased and QoS mechanisms should be introduced in multiprocessor interconnects. This study suggests several methods to build multiprocessor interconnects in ATCA and discusses them in the view of redundancy, congestion handling ability, and implementation feasibility

Demonstration of packet-optic integrated transport system

We propose and experimentally demonstrate a packet optical integrated transport system. The proposed system supports packet transport layer features based on PBB-TE. The restoration time from a link failure is measured to be about 20 ms and 11.8 ms, respectively, in the packet transport layer and optical transport layer. The measured restoration time is much smaller than the 50 ms industry requirement for real-time services. The fast restoration time allows the proposed packet-optic integrated transport system to offer high availability and reliability which is a requirement for transport networks.

High available system control network in the packet transport system

This paper is about design and buildup of multiprocessor interconnects in the packet transport system. To keep pace with expansion and growth of internet and data communication, constant enhancement and upgrade of packet transport system is required. As network adopts new services like IPTV, VoIP, and VLAN, processing power of packet transport system should be easily and dynamically added to the system for supporting highly compute-power requiring jobs. The processing power of system depends on the number of processors, the clock speed of each processor, efficiency of operation system in data centric processing, proper distribution of system works, and robust and high bandwidth interconnects (system control network) among processors. This paper suggested several methods for the system control networking in the packet transport system and reviewed each method in the view of internal and external expansion of system control network, loop elimination, and redundancy support.

A new design methodology of cardiac output control scheme for the moving actuator type total artificial heart (TAH)

A new methodology in designing an automatic cardiac output controller for a TAH is proposed. The control scheme has flexibility in preload sensitivity. The proposed controller was evaluated for 1 week with a calf.