Hyunwoo Nam

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PURPOSE Application of independent component analysis (ICA) to interictal EEGs and to event-related potentials has helped noise reduction and source localization. However, ICA has not been used for the analysis of ictal EEGs in partial seizures. In this study, we applied ICA to the ictal EEGs of patients with medial temporal lobe epilepsy (TLE) and(More)
Adaptive bitrate (ABR) technologies are being widely used in today's popular HTTP-based video streaming such as YouTube and Netflix. Such a rate-switching algorithm embedded in a video player is designed to improve video quality-of-experience (QoE) by selecting an appropriate resolution based on the analysis of network conditions while the video is playing.(More)
—Slow Internet connectivity is often caused by poor Wi-Fi performance. The main reasons of such performance degradation include channel contention and non-Wi-Fi interference. Although these problem sources can be easily removed in many cases once they are discovered, it is difficult for end users to identify the sources of such interference. We investigated(More)
BACKGROUND AND PURPOSE Restless legs syndrome (RLS) is a sleep disorder that frequently occurs in dialysis patients, which disturbs the sleep and reduces the quality of life. The aim of this study was to determine the risk factors for RLS in dialysis patients. METHODS Patients who visited any of four outpatient dialysis clinics between September 2005 and(More)
—Today's over the top (OTT) video service providers take advantage of content distribution networks (CDNs) and adaptive bitrate (ABR) streaming where a video player adjusts resolutions based on end-to-end network conditions. Although the mechanisms are useful to improve user-perceived video quality, they do not resolve the root causes of congestion(More)
—We investigate video server selection algorithms in a distributed video-on-demand system. We conduct a detailed study of the YouTube Content Delivery Network (CDN) on PCs and mobile devices over Wi-Fi and 3G networks under varying network conditions. We proved that a location-aware video server selection algorithm assigns a video content server based on(More)
—With the proliferation of online video, measuring quality of experience (QoE) has become a pivotal aspect for the analysis of today's over-the-top (OTT) video streaming. For monitoring video QoE, we introduce YouSlow that can detect various playback events (e.g., start-up latency, rebufferings and bitrate changes) from video players while a video is being(More)
—Existing failure diagnostic techniques for end users are insufficient to pinpoint the root causes of network failures due to their limited capabilities to probe other network elements. We present DYSWIS, an automatic network fault detection and diagnosis system for end-users. DYSWIS leverages user collaboration to distinguish important network faults from(More)
BACKGROUND Patients with amyotrophic lateral sclerosis (ALS) suffer from hypoventilation, which can easily worsen during sleep. This study evaluated the efficacy of capnography monitoring in patients with ALS for assessing nocturnal hypoventilation and predicting good compliance with subsequent noninvasive ventilation (NIV) treatment. METHODS Nocturnal(More)