• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.18-21
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• 2005

The impact of the interannual climatic variability on the vegetation sensitively appears in the timing of phenological events such as green-up, mature, and senescence. Therefore, an accurate and temporally high-resolution NDVI dataset will be required for analysis on the interannual variability of the climate-vegetation relationship. We constructed a daily 8km NDVI dataset over Eurasia based on the 8km tiled data of Pathfinder A VHRR Land (PAL) Global daily product. Cloud contamination was successfully reduced by Temporal Window Operation (TWO), which is a method to find optimized upper envelop line of the NDVI seasonal change. Based on the daily NDVI time series from 1982 to 2000, an accurate (daily) interannual change of the phenological events will be analyzed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.4
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• pp.294-303
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• 2023

During wartime, the operation of engineering equipment plays a pivotal role in bolstering the combat prowess of military units. To fully harness this combat potential, it is imperative to provide efficient support precisely when and where it is needed most. While previous research has predominantly focused on optimizing equipment combinations to expedite individual mission performance, our model considers routing challenges encompassing multiple missions and temporal constraints. We implement a comprehensive analysis of potential wartime missions and developed a routing model for the operation of engineering equipment that takes into account multiple missions and their respective time windows of required start and completion time. Our approach focused on two primary objectives: maximizing overall capability and minimizing mission duration, all while adhering to a diverse set of constraints, including mission requirements, equipment availability, geographical locations, and time constraints.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.1885-1896
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• 1996

This paper describes the implementation of the AVT(Automatic video Tracker) using ASIC. The basic tracking algorithm is based on the spatio-temporal gradient method, and adaptive window sizing, track state decision algorithm were also realized. Newly developed ASIC performs recursive image filtering, extraction of spatio-temporal gradient/gradient functions of image in field rate. Using the FPGA/ASIC, the tracker was simply realized in one board type which can be easily applied to various image system. We conformed ASIC operation by computer simulation and tested the system in real tracking situations. From the result, the system can track the moving target which has a velocity of 2-3 pixel/field and a size of varying from 2 to 128 pixes. Also fast refresh rateof motion estimation(60Hz) improves the characteristics of servoing system which forms feedback loop with the tracker.

• Journal of Biomedical Engineering Research
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• v.17 no.2
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• pp.179-188
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• 1996

A clinically oriented 32-channel electroencephalogram (EEG) and evoked potential (EP) mapping system has been developed EEG and EP signals acquired from 32-channel electrodes attached on the heroid surface are amplified by a pre-amplifier which is separated from main amplifier and is located near the patient to reduce signal attenuation and noise contamination between electrodes and the amplifier. The amplified signals are further amplified by a main amplifier where various filtering and gain contr61 are achieved An automatic artifact rejection scheme is employed using neural network-based EEG and artifact classifier, by which examination time is substantially reduce4 The continuously measured EEG sigrlals are used for spectral mapping, and auditory and visual evoked potentials measured in synchronous to the auditory and visual stimuli are used for temporal evoked potential mapping. A user-friendly graphical interface based on the Microsoft Window 3.1 is developed for the operation of the system. Statistical databases for comparisons of group and individual are included to support a statistically-based diagnosis.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.3
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• pp.258-268
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• 2001

The compression method is necessarily used to send the high quality moving picture that contains a number of data in image processing. In the field of moving picture compression method, the motion estimation algorithm is used to reduce the temporal redundancy. Block matching algorithm to be usually used is distinguished partial search algorithm with full search algorithm. Full search algorithm be used in this paper is the method to compare the reference block with entire block in the search window. It is very efficient and has simple data flow and control circuit. But the bigger the search window, the larger hardware size, because large computational operation is needed. In this paper, we design the full search block matching motion estimator. Using the DCT DC values, we decide luminance. And we apply 3 bit compare-selector using bit plane to I(Intra coded) picture, not using 8 bit luminance signals. Also it is suggested that use the same selective bit for the P(Predicted coded) and B(Bidirectional coded) picture. We compare based full search method with PSNR(Peak Signal to Noise Ratio) for C language modeling. Its condition is the reference block 8$\times$8, the search window 24$\times$24 and 352$\times$288 gray scale standard video images. The result has small difference that we cannot see. And we design the suggested motion estimator that hardware size is proved to reduce 38.3％ for structure I and 30.7％ for structure II. The memory is proved to reduce 31.3％ for structure I and II.

• Journal of the Korean Society for Library and Information Science
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• v.52 no.3
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• pp.171-192
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• 2018

With the spread of the maker movement and matching of the standards for the 21st century learners and the maker competencies, there is a social and temporal need for makerspaces building and maker education in school libraries, Prior to the establishment of the school library makerspaces, we intended to investigate the awareness of the school librarian on the creation and operation of the school library makerspaces. For this purpose, a questionnaire was constructed based on the theoretical review and the response data of 171 school librarians were collected through a web survey. Technical statistics, cross-analysis, and ANOVA were conducted using SPSS window 19.0 and content analysis was conducted on open-ended questions. The Questionnaires consisted of questions about whether the school library makerspace was installed or not and necessity, reason, and difficulty in creating and operating the makerspace. As a result of the study, it was found that the establishment of the school library makerspace was very low at 2.3%, and the recognition of the makerspace of the school librarian was below the normal level. On the other hand, the perception of necessity appeared to be more than normal, and the school library was generally considered to be a suitable place for the makerspace installation. However, negative opinions about the school library makerspaces were also raised in various aspects.

• Journal of Korean Neurosurgical Society
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• v.65 no.6
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• pp.816-824
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• 2022

Objective : Emergency superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis in patients with large vessel occlusion who fails mechanical thrombectomy or does not become an indication due to over the time window can be done as an alternative for blood flow restoration. The authors planned this study to quantitatively measure the degree of improvement in cerebral perfusion flow using perfusion magnetic resonance imaging (MRI) after bypass surgery and to find out what factors are related to the outcome of the bypass surgery. Methods : For a total of 107 patients who underwent emergent STA-MCA bypass surgery with large vessel occlusion, the National Institute of Health stroke scale (NIHSS), modified Rankin score (mRS), infarction volume, and hypoperfusion area volume was calculated, the duration between symptom onset and reperfusion time, occlusion site and infarction type were analyzed. After emergency STA-MCA bypass, hypoperfusion area volume at post-operative 7 days was calculated and analyzed compared with pre-operative hypoperfusion area volume. The factors affecting the improvement of mRS were analyzed. The clinical status of patients who underwent emergency bypass was investigated by mRS and NIHSS before and after surgery, and changes in infarct volume, extent, degree of collateral circulation, and hypoperfusion area volume were measured using MRI and digital subtraction angiography (DSA). Results : The preoperative infarction volume was median 10 mL and the hypoperfusion area volume was median 101 mL. NIHSS was a median of 8 points, and the last normal to operation time was a median of 60.7 hours. STA patency was fair in 97.1% of patients at 6 months follow-up DSA and recanalization of the occluded vessel was confirmed at 26.5% of patients. Infarction volume significantly influenced the improvement of mRS (p=0.010) but preoperative hypoperfusion volume was not significantly influenced (p=0.192), and the infarction type showed marginal significance (p=0.0508). Preoperative NIHSS, initial mRS, occlusion vessel type, and last normal to operation time did not influence the improvement of mRS (p=0.272, 0.941, 0.354, and 0.391). Conclusion : In a patient who had an acute cerebral infarction due to large vessel occlusion with large ischemic penumbra but was unable to perform mechanical thrombectomy, STA-MCA bypass could be performed. By using time-to-peak images of perfusion MRI, it is possible to quickly and easily confirm that the brain tissue at risk is preserved and that the ischemic penumbra is recovered to a normal blood flow state.

• Journal of Biosystems Engineering
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• v.39 no.1
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• pp.47-56
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• 2014

Purpose: In protected crop production facilities such as greenhouse and plant factory, farmers should be present and/or visit frequently to the production site for maintaining optimum environmental conditions and better production, which is time and labor consuming. Monitoring of environmental condition is highly important for optimum control of the conditions, and the condition is not uniform within the facility. Objectives of the paper were to investigate spatial and vertical variability in ambient environmental variables and to provide useful information for sensing and control of the environments. Methods: Experiments were conducted in a strawberry-growing greenhouse (greenhouse 1) and a cherry tomato-growing greenhouse (greenhouse 2). Selected ambient environmental variables for experiment in greenhouse 1 were air temperature and humidity, and in greenhouse 2, they were air temperature, humidity, PPFD (Photosynthetic Photon Flux Density), and $CO_2$ concentration. Results: Considerable spatial, vertical, and temporal variability of the ambient environments were observed. In greenhouse 1, overall temperature increased from 12:00 to 14:00 and increased after that, while RH increased continuously during the experiments. Differences between the maximum and minimum temperature and RH values were greater when one of the side windows were open than those when both of the windows were closed. The location and height of the maximum and minimum measurements were also different. In greenhouse 2, differences between the maximum and minimum air temperatures at noon and sunset were greater when both windows were open. The maximum PPFD were observed at a 3-m height, close to the lighting source, and $CO_2$ concentration in the crop growing regions. Conclusions: In this study, spatial, vertical, and temporal variability of ambient crop growing conditions in greenhouses was evaluated. And also the variability was affected by operation conditions such as window opening and heating. Results of the study would provide information for optimum monitoring and control of ambient greenhouse environments.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.1
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• pp.63-71
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• 2017

In this paper, a signal processing circuit for semi-implantable middle ear hearing device is designed using the TCBT which is recently proposed for a new middle ear transducer that can be implanted at round window of cochlea. The designed semi-implantable hearing device transmits digital sound signal from external device located at behind the ear to the internal device implanted under the skin using inductive coupling link methods with high efficiency. The coils and signal processing circuits are designed and implemented considering the total transmission and reception distance including skin thickness of temporal bone for the semi-implantable hearing device. And also, to improve the data transmission efficiency, the output circuits which can supply sufficient signal power is designed. In order to confirm operation of semi-implantable hearing device using inductive coupling link, the circuit analysis was performed using PSpice, and the performance was verified by implementing a signal processing board of an available size.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1289-1295
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• 2000

Purpose : Recent evidence suggests a possible role for leukocytes in brain injury following ischemia and reperfusion. This study examined the temporal profile of ischemic tissue damage and leukocyte response after transient middle cerebral artery occlusion(MCAO) with reperfusion in the mouse. Methods : Focal cerebral ischemia was made by temporary occluding of the stem of the proximal MCA. Two groups of the mouse were investigated : (1) sham operation(n＝10), and (2)those having the arterial occlusion released after 90 minute(n＝20). By 4 hours(n＝10) and 24 hours(n＝10) after the onset of ischemia-reperfusion, fluorescein videoimages were under-taken in the pial venules of the mouse using a closed cranial window technique. Rhodamine 6G was administered as a $80-100{\mu}l/min$ i.v. loading dose and a $30-40{\mu}l/min$ i.v. maintenance dose in saline to selectively label circulating leukocytes. Neuropathologic evaluation for brain injury was accomplished using the histochemical stain 2,3,5-triphen-yltetrazolium chloride(TTC) and hematoxylin and eosin(H & E) stain. Results : The mean number of adherent leukocytes to cerebral venules in the 90 minutes MCAO and 24 hours reperfusion group were $306{\pm}24$ compared with $72{\pm}8$ in the sham operation group. In the TTC staining method, the cortical infarct affecting 34.8% of hemispheric volume were created in all of animals (n＝10) undergoing 90 minute MCAO with 24 hours reperfusion, but the infarcted area were not found in the other(sham operation and 90 minute MCAO with 4 hours reperfusion)groups. In the H & E stain, the brain tissue following 90 minute MCAO with 4 hours reperfusion revealed only a pyknosis of the nuclei with shrunken cytoplasm, but infiltrated leukocytes were not observed. After 24 hours of reperfusion, a many leukocytes were infiltrated within parenchyma and blood vessles. Conclusions : These findings demonstrate the feasiblity of continous in vivo monitoring of leukocyte adherence in cerebral venules and suggest that reperfusion induced leukocyte adherence to venular endothelium may contribute to tissue injury following focal cerebral ischemia.