• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.327-329
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• 2017

We report a spatial fluctuation analysis of the sky brightness in the near-infrared from observations towards the north ecliptic pole (NEP) by AKARI at 2.4 and $3.2{\mu}m$. As a follow up study of our previous work on the Monitor field of AKARI, we used NEP deep survey data, which covered a circular area of about 0.4 square degrees, in order to extend fluctuation analysis at angular scales up to 1000". After pre-processing, additional correction procedures were done to correct time varying components and instrumental effects such as MUXbleed. To remove resolved objects, we applied $2{\sigma}$ clipping and point spread function (PSF) subtraction. We finally obtained mosaicked images which can be used for the study of various diffuse emissions in the near-infrared sky and found that there are spatial structures in the mosaicked images using a power spectrum analysis.

• Journal of Korean Neurosurgical Society
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• v.49 no.5
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• pp.287-289
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• 2011

Thalamoperforating artery aneurysms are rarely reported in the literature. We report an extremely rare case of ruptured distal anterior thalamoperforating artery aneurysm which was treated by endovascular obliteration in a patient with occlusion of both the internal carotid arteries (ICAs) : A 72-year-old woman presented with severe headache and loss of consciousness. Initial level of consciousness at the time of admission was drowsy and the Glasgow Coma Scale score was 14. Brain computed tomography (CT) scan was performed which revealed intracerebral hemorrhage in right basal ganglia, subarachnoid hemorrhage, and intraventricular hemorrhage. The location of the aneurysm was identified as within the globus pallidus on CT angiogram. Conventional cerebral angiogram demonstrated occlusion of both the ICAs just distal to the fetal type of posterior communicating artery and the aneurysm was arising from right anterior thalamoperforating artery (ATPA). A microcatheter was navigated into ATPA and the ATPA proximal to aneurysm was embolized with 20% glue. Post-procedural ICA angiogram demonstrated no contrast filling of the aneurysm sac. The patient was discharged without any neurologic deficit. Endovascular treatment of ATPA aneurysm is probably a more feasible and safe treatment modality than surgical clipping because of the deep seated location of aneurysm and the possibility of brain retraction injury during surgical operation.

• Speech Sciences
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• v.10 no.2
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• pp.85-95
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• 2003

In speech signal processing, it is very important to detect the pitch exactly in speech recognition, synthesis and analysis. If we exactly pitch detect in speech signal, in the analysis, we can use the pitch to obtain properly the vocal tract parameter. It can be used to easily change or to maintain the naturalness and intelligibility of quality in speech synthesis and to eliminate the personality for speaker-independence in speech recognition. In this paper, we proposed a new pitch detection algorithm. First, positive center clipping is process by using the incline of speech in order to emphasize pitch period with a glottal component of removed vocal tract characteristic in time domain. And rough formant envelope is computed through peak-fitting spectrum of original speech signal infrequence domain. Using the roughed formant envelope, obtain the smoothed formant envelope through calculate the linear interpolation. As well get the flattened harmonics waveform with the algebra difference between spectrum of original speech signal and smoothed formant envelope. Inverse fast fourier transform (IFFT) compute this flattened harmonics. After all, we obtain Residual signal which is removed vocal tract element. The performance was compared with LPC and Cepstrum, ACF. Owing to this algorithm, we have obtained the pitch information improved the accuracy of pitch detection and gross error rate is reduced in voice speech region and in transition region of changing the phoneme.

• Speech Sciences
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• v.9 no.4
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• pp.237-252
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• 2002

MIT has been applied for nonfluent aphasic patients on the basis of lateralization of brain hemisphere. However, its applications for different languages have some inquiry for aphasic patients because of prosodic and rhythmic differences. The purpose of this study is to develop the Korean Melodic Intonation Therapy program using personal computer and its clinical effects for nonfluent aphasic patients. The algorithm was composed to voice analog signal, PCM, AMDF, Short-time autocorrelation function and center clipping. The main menu contains pitch, waveform, sound intensity and speech files on window. Aphasic patients' intonation patterns overlay on selected kMIT patterns. Three aphasic patients with or without kMIT training participated in this study. Four affirmative sentences and two interrogative sentences were uttered on CSL by stimulus of ST. VOT, VD, Hold and TD were measured on Spectrogram. In addition, articulation disorders and intonation patterns were evaluated objectively on spectrogram. The results indicated that nonfluent aphasic patients with kMIT training group showed some clinical effects of speech intelligibility based on VOT, TD values, articulation evaluation and prosodic pattern changes.

• Journal of Veterinary Clinics
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• v.22 no.2
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• pp.136-140
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• 2005

This experiment is designed to determine the relationship between groomers' activities and stress. The experimenter worked with 2 female dogs and 3 male dogs owned by clients. They were 22 months old on an average and weighed 5.5kg on an average. The concentration of cortisol in blood was measured with radioimmunoassy(RIA). The concentration of cortisol in blood was high in the morning and evening and was low in the afternoon. In a normal condition, the concentration of cortisol in blood was $1.4{\mu}g/dL$, which increased to $4.98{\mu}g/dL$ after 1 hr of grooming, and then returned to normal at the termination of grooming. The survey shows that grooming acted as a stressor, which seems to have an influence on the health of dogs. So it is absolutely necessary that systematic and constant research should be conducted to reduce stress at the time of grooming.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.315-321
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• 2011

Since the MB-OFDM(Multi-Band Orthogonal Frequency Division Multiplexing) is an ultra wideband communication system operated on ISM(Industrial, Scientific and Medical) band, DAA(Detect-And-Avoid) is required for co-existence with the other communication service. In this paper we propose the new detection algorithm based on decision-feedback, which shows faster convergence time and less complexity than previous works. The proposed algorithm detects interference above -20dB in AWGN(Additive White Gaussian Noise) and LOS(Line-Of-Sight) channel, and close to AWGN in non-LOS channel under appropriate channel clipping.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.20 no.4
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• pp.241-247
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• 2018

Treatment of paraclinoid aneurysms weather by surgery, or endovascular embolization has a risk of visual loss due to optic neuropathy, or diplopia due to cranial nerve palsies. Visual complications occur immediately after the clipping, whereas they can occur variable time after endovascular coiling. Recently, endovascular coiling for paraclinoid aneurysm is regarded as a safe and feasible treatment. But it still has risks of acute thromboembolic complication, or cranial nerve palsies. A 45-year-old woman was referred from local hospital to our hospital due to ruptured large ICA dorsal wall aneurysm. A total of 12 coils (195 cm) were used for obliteration of aneurysm. Postoperative diffusion weighted image showed no abnormal signal intensity lesion and magnetic resonance angiography demonstrated no sign of vasospasm, or vessel narrowing. But, she complained visual problem 23 days after coil embolization. Ophthalmologist confirmed the left optic disc atrophy on fundoscopy. Although steroid was started, but monocular blindness did not recover completely. The endovascular embolization of paraclinoid aneurysm, especially projecting superiorly with large irregular shape, has the risk of progressive visual loss because of the proximity to optic nerve.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.71-80
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• 2007

This paper presents a new push-push VCO technique that extracts a second harmonic output signal from a capacitive commonnode in a negativegm oscillator topology. The generation of the $2^{nd}$ harmonics is accounted for by the nonlinear current-voltage characteristic of the emitter-base junction diode causing; 1) significant voltage clipping and 2) different rising and falling time during the switching operation of core transistors. Comparative investigations show the technique is more power efficient in the high-frequency region that a conventional push-push technique using an emitter common node. Prototype 12GHz and 17GHz MMIC VCO were realized in GaInP/GaAs HBT technology. They have shown nominal output power of -4.3dBm and -5dBm, phase noise of -108 dBc/Hz and -110.4 dBc/Hz at 1MHz offset, respectively. The phase noise results are also equivalent to a VCO figure-of-merit of -175.8 dBc/Hz and -184.3 dBc/Hz, while dissipate 25.68mW(10.7mA/2.4V) and 13.14mW(4.38mA/3.0V), respectively.

• Journal of Korean Neurosurgical Society
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• v.30 no.7
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• pp.891-895
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• 2001

Objective : Although surgical clipping of intracranial aneurysm is the definite method of treatment, there remains a small number of patients in whom surgical clipping is not technically possible. In such difficult cases, surgeon has to consider other therapeutic alternatives. In this report, we analyze our aneurysmal cases treated by wrapping and coating method and evaluate their surgical outcome and follow-up results. Method : Among the total of 877 patients operated from 1990 to 1999 for intracranial aneurysms at our hospital, 40 cases(4.6%) were treated by wrapping and coating method. They included 24 cases of single ruptured aneurysms and 16 with unruptured ones in multiple aneurysms. Wrapping with temporalis muscle and/or muslin gauze and coating with bioadhesive agent such as fibrin glue were performed. Result : Wrapping and coating method was performed mostly to the anterior communicating artery aneurysm (35%), and mostly because of the broad-based neck of an aneurysm(43%). At the time of discharge, 30 out of 40 patients(80%) showed favourable outcome and three cases died. The patients were monitored for average of 37 months(3-75 months). Among 24 cases with single ruptured aneurysm, 4 cases(17%) had early rebleeding within 6 months from the initial hemorrhage, and such rebleeding occurred within the first postoperative month in 3 cases. However, there was no rebleeding after the 6 months. Among 16 patients whose aneurysms were unruptured ones, none of them showed bleeding episode. Conclusion : It seems likely that the wrapping and coating method would be some help to prevent the rebleeding of an intracranial aneurysm. In order to obtain more accurate results regarding the efficacy of such method, it will be necessary to perform a multi-center study for longer follow-up periods and various wrapping and coating materials.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.1
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• pp.50-61
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• 2023

Objective: To describe the roadmapping technique and our three-year experience in the management of intracranial aneurysms in the hybrid operating room. Methods: We analyzed all patients who underwent surgical clipping for cerebral aneurysms with the roadmapping technique from January 2017 to September 2019. We report demographic, clinical, and morphological variables, as well as clinical and radiological outcomes. We further describe three illustrative cases of the technique. Results: A total of 13 patients were included, 9 of which (69.2%) presented with subarachnoid hemorrhage, with a total of 23 treated aneurysms. All patients were female, with a mean age of 47.7 years (range 31-63). All cases were anterior circulation aneurysms, the most frequent location being the ophthalmic segment of the internal carotid artery (ICA) in 11 cases (48%), followed by posterior communicating in 8 (36%), and ICA bifurcation in 2 (8%). Intraoperative clip repositioning was required in 9 aneurysms (36%) as a result of the roadmapping technique in the hybrid operating room. There were no residual aneurysms in our series, nor reported mortality. Conclusions: The roadmapping technique in the hybrid operating room offers a complementary tool for the adequate occlusion of complex intracranial aneurysms, as it provides a real time fluoroscopic-guided clipping technique, and clip repositioning is possible in a single surgical stage, whenever a residual portion of the aneurysm is identified. This technique also provides some advantages, such as immediate vasospasm identification and treatment with intra-arterial vasodilators, balloon proximal control for certain paraclinoid aneurysms, and simultaneous endovascular treatment in selected cases during a single stage.