Sung Hyun Lee

Bio: Sung Hyun Lee is an academic researcher from Hanyang University. The author has contributed to research in topics: Video compression picture types & Frame (networking). The author has an hindex of 3, co-authored 3 publications receiving 77 citations.

Multi-center study on migraine and seizure-related headache in patients with epilepsy

Abstract: Purpose The purpose of this study is to investigate the frequency and characteristics of migraine and seizure-related headache (SRH) according to the criteria of the International Headache Society. Materials and Methods A questionnaire was undertaken at the initial evaluation of newly referred patients from 32 epilepsy clinics. Results Of a total of 597 patients, 74 (12.4%) patients had migraine. Age at the onset of epilepsy was lower in patients with migraine than in those without. Twenty-six (4.4%), nine (1.5%), and 146 (24.5%) patients experienced prodromal, ictal, and postictal SRH, respectively (n = 169, 28.3%). A pain intensity of prodromal and postictal SRH was 6.1 ± 1.5 (SD) and 6.3 ± 1.9 (SD) on the visual analogue scale, and their duration was 12.6 ± 26.7 (SD) hours and 9.0 ± 17.4 (SD) hours, respectively. Age at the onset of epilepsy was lower in patients with SRH than in those without, and the risk of occurrence of SRH was significantly greater in patients with longer epilepsy duration. SRH could be classified as a type of migraine in 46.2% of patients with prodromal SRH and in 36.3% of patients with postictal SRH. Prodromal SRH occurred more frequently and was more likely to be a migraine-type in patients with migraine compared with those without. Postictal SRH occurred more frequently and was more likely to be a migraine-type in patients with migraine. Conclusion This study suggests that SRH is a frequent accompanying symptom of epileptic seizures causing major impairment in daily life, and migraine is an important comorbidity of epilepsy, affecting the incidence and characteristics of SRH.

Adaptive video watermarking utilizing video characteristics in 3D-DCT domain

Abstract: In this paper, we propose an adaptive blind video watermarking method using video characteristics based on human visual system (HVS) in three-dimensional discrete cosine transform (3D-DCT) domain. In order to optimize the weight factors for watermarking, we classify the patterns of 3D-DCT cubes and the types of video segments by using the texture and motion information of 3D-DCT cubes. Then we embed an optimal watermark into the mid-range coefficients of 3D-DCT cubes by using the trained optimal weight factors. Experimental results show that the proposed method achieves better performance in terms of invisibility and robustness than the previous method under the various possible attacks such as MPEG compression, frame dropping, frame insertion and frame swapping to experimental videos.

Adaptive video watermarking utilizing video characteristics in 3D-DCT domain

Abstract: In this paper, we propose an adaptive blind video watermarking method using video characteristics based on human visual system (HVS) in three-dimensional discrete cosine transform (3D-DCT) domain. In order to optimize the weight factors for watermarking, we classify the patterns of 3D-DCT cubes and the types of video segments by using the texture and motion information of 3D-DCT cubes. Then we embed an optimal watermark into the mid-range coefficients of 3D-DCT cubes by using the trained optimal weight factors. Experimental results show that the proposed method achieves better performance in terms of invisibility and robustness than the previous method under the various possible attacks such as MPEG compression, frame dropping, frame insertion and frame swapping to experimental videos.

Epileptic seizures and headache/migraine: A review of types of association and terminology

Abstract: Purpose There are different possible temporal associations between epileptic seizures and headache attacks which have given rise to unclear or controversial terminologies. The classification of the International League Against Epilepsy does not refer to this type of disorder, while the International Classification of Headache Disorders (ICHD-2) defines three kinds of association: 1. migraine-triggered seizure ("migralepsy"), 2. hemicrania epileptica, and 3. post-ictal headache. Methods We performed an extensive review of the literature, not including "post-ictal" and "inter-ictal" headaches. Results On the basis of well-documented reports, the following clinical entities may be identified: (A) "epileptic headache (EH)" or "ictal epileptic headache (IEH)": in this condition headache (with or without migrainous features) is an epileptic manifestation per se , with onset, and cessation if isolated, coinciding with the scalp or deep EEG pattern of an epileptic seizure. EH maybe followed by other epileptic manifestations (motor/sensory/autonomic); this condition should be differentiated from "pure" or "isolated" EH, in which headache/migraine is the sole epileptic manifestation (requiring differential diagnosis from other headache forms). "Hemicrania epileptica" (if confirmed) is a very rare variant of EH, characterized by ipsilateral location of headache and ictal EEG paroxysms. (B) "Pre-ictal migraine" and "pre-ictal headache": when a headache attack is followed during, or shortly after, by a typical epileptic seizure. The migraine attack may be with or without aura, and its seizure-triggering role ("migraine-triggered seizure") is still a subject of debate. A differentiation from occipital epilepsy is mandatory. The term "migralepsy" has not been used uniformly, and may therefore led to misinterpretation. Conclusions On the basis of this review we suggest definitions and a terminology which may become the basis of a forthcoming classification of headaches associated with epileptic seizures.

Video Watermarking With Empirical PCA-Based Decoding

Abstract: A new method for video watermarking is presented in this paper. In the proposed method, data are embedded in the LL subband of wavelet coefficients, and decoding is performed based on the comparison among the elements of the first principal component resulting from empirical principal component analysis (PCA). The locations for data embedding are selected such that they offer the most robust PCA-based decoding. Data are inserted in the LL subband in an adaptive manner based on the energy of high frequency subbands and visual saliency. Extensive testing was performed under various types of attacks, such as spatial attacks (uniform and Gaussian noise and median filtering), compression attacks (MPEG-2, H. 263, and H. 264), and temporal attacks (frame repetition, frame averaging, frame swapping, and frame rate conversion). The results show that the proposed method offers improved performance compared with several methods from the literature, especially under additive noise and compression attacks.

Headache in epilepsy: prevalence and clinical features

Abstract: Headache and epilepsy are two relatively common neurological disorders and their relationship is still a matter of debate. Our aim was to estimate the prevalence and clinical features of inter-ictal (inter-IH) and peri-ictal headache (peri-IH) in patients with epilepsy. All patients aged ≥ 17 years referring to our tertiary Epilepsy Centre were consecutively recruited from March to May 2011 and from March to July 2012. They underwent a semi-structured interview including the International Classification Headache Disorders (ICHD-II) criteria to diagnose the lifetime occurrence of headache.χ2-test, t-test and Mann–Whitney test were used to compare clinical variables in patients with and without inter-IH and peri-IH. Out of 388 enrolled patients 48.5 % had inter-IH: migraine in 26.3 %, tension-type headache (TTH) in 19.1 %, other primary headaches in 3.1 %. Peri-IH was observed in 23.7 %: pre-ictally in 6.7 %, ictally in 0.8 % and post-ictally in 19.1 %. Comparing patients with inter-ictal migraine (102), inter-ictal TTH (74) and without inter-IH (200), we found that pre-ictal headache (pre-IH) was significantly represented only in migraineurs (OR 3.54, 95 % CI 1.88-6.66, P < 0.001). Post-ictal headache (post-IH) was significantly associated with both migraineurs (OR 2.60, 95 % CI 1.85-3.64, P < 0.001) and TTH patients (OR 2.05, 95 % CI 1.41-2.98, P < 0.001). Moreover, post-IH was significantly associated with antiepileptic polytherapy (P < 0.001), high seizure frequency (P = 0.002) and tonic-clonic seizures (P = 0.043). Migraine was the most represented type of headache in patients with epilepsy. Migraineurs are more prone to develop pre-IH, while patients with any inter-IH (migraine or TTH) are predisposed to manifest a post-IH after seizures.

Headache in patients with epilepsy: a prospective incidence study.

Abstract: High prevalence of headache has been reported in patients with refractory epilepsy in cross-sectional surveys based on retrospective recall We conducted a prospective study to document the incidence of headache over a 3-month observation period in a cohort of 227 adult patients with less refractory epilepsy The mean seizure frequency was 246 per month Fifty (22%) patients reported to have had at least one headache episode, 45 (198%) had interictal headache, 11 (48%) had periictal headache, and 5 (22%) had both interictal and periictal headache Forty-nine percent of the patients with headache took over-the-counter analgesics as acute treatment The headache was rated to have made very severe or substantial impact on their lives by 34% of patients A formal headache diagnosis was not made in any of the patients prior to the survey Although the incidence of headache in epilepsy patients appeared to be low, it was underdiagnosed and associated with substantial negative impact