• Journal of Korean Neurosurgical Society
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• v.64 no.2
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• pp.229-237
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• 2021

Objective : Expansion in the spinal canal area (SCA) after laminoplasty is one of the critical factors to relieve the preoperative symptoms. No previous study has compared the increases in SCA achieved by open-door laminoplasty (ODL) and double door laminoplasty (DDL) according to the preoperative lamina angle (LA). This study was designed to clarify the relationship between the laminoplasty opening angle (OA)/laminoplasty opening size (OS) and increases in the SCA following ODL and DDL according to the preoperative LA using a simulation model. Methods : The simulation model was constructed and validated by comparing the clinical data of 64 patients who had undergone C3-C6 laminoplasty (43 patients with ODL and 21 patients with DDL). SCA expansion was predicted with a verified simulation model at various preoperative LAs (from 28° to 32°) with different OAs (40° to 44°) and OSs (10 mm to 14 mm) recruited from patient data. Results : The constructed simulation model was validated by comparing clinical data and revealed a very high degree of correlation (r=0.935, p<0.001). In this validated model, at the same OA, the increase in SCA was higher following ODL than following DDL in the usual LA (p<0.05). At the same OS, the increase in SCA was slightly larger following DDL than following ODL, but the difference was not significant (p>0.05). The difference was significant when the preoperative LA was narrower or much wider. Conclusion : Based on clinical data, a simulation model was constructed and verified that could predict increases in the SCA following ODL and DDL. When applying this model, prediction in SCA increase using the OS parameter was more practical and compatible with clinical data. Both laminoplasties achieved enough SCA, and there was no significant difference between them in the usual range.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.1
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• pp.125-136
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• 2020

This study aims to seek a proper policy direction in response to the demand for apartment remodeling. As the research methods, we diagnosed the current status of the remodeling policy and analyzed the demand for apartment remodeling nationwide. According to the result of analysis, we suggested the fundamental direction and tasks for remodeling policies to be pursued at the government level. The results of the study are summarized as follows. First, the result of analysis showed that the demand for environmental improvement(performance improvement) remodeling project was much higher than other types of remodeling projects. The percentage of unit increased-type remodeling that can secure business feasibility is about 10% and only 30% when it comes to reducing project costs. The remaining 70-90% need to be promoted in environmental improvement remodeling projects which dependent on the residents' payment. Second, in order to prepare a policy action plan in response to the demand for apartment remodeling, it is necessary to set up clear policy goals and strategies for apartment remodeling in advance at the national level. Along with proactive goals and strategies, graded policy support should be accompanied per type of remodeling and business demand. We also suggest to simplify administrative procedures and support the R&D research to develop technologies. It would help to utilize the unit increased-type remodeling. On the other hand, for utilizing the environmental improvement remodeling which takes up a relatively high proportion, the policy should take care of as follows: offering housing performance information, rationalizing long term repair reserve, fostering small companies and experts. Finally, apartment management system should be advanced from the perspectives of managing old apartments and institutional foundations such as new construction and customized regulations for differentiated remodeling should be accompanied.

• Archives of Craniofacial Surgery
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• v.22 no.1
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• pp.33-37
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• 2021

Background: Children with cleft lip and/or palate can be undernourished due to feeding difficulties after birth. A vicious cycle ensues where malnutrition and low body weight precludes the child from having the corrective surgery, in the absence of which the child fails to gain weight. This study aimed to identify the proportion of malnutrition, including the deficiency of major micronutrients, namely iron, folate and vitamin B12, in children with cleft lip and/or palate and thus help in finding out what nutritional interventions can improve the scenario for these children. Methods: All children less than 5 years with cleft lip and/or cleft palate attending our institute were included. On their first visit, following were recorded: demographic data, assessment of malnutrition, investigations: complete blood count and peripheral blood film examination; serum albumin, ferritin, iron, folate, and vitamin B12 levels. Results: Eighty-one children with cleft lip and/or palate were included. Mean age was 25.37±21.49 months (range, 3-60 months). In 53% of children suffered from moderate to severe wasting, according to World Health Organization (WHO) classification. Iron deficiency state was found in 91.6% of children. In 35.80% of children had vitamin B12 deficiency and 23.45% had folate deficiency. No correlation was found between iron deficiency and the type of deformity. Conclusion: Iron deficiency state is almost universally present in children with cleft lip and palate. Thus, iron and folic acid supplementation should be given at first contact to improve iron reserve and hematological parameters for optimum and safe surgery.

• Journal of Korean Society of Forest Science
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• v.100 no.3
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• pp.494-503
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• 2011

This study was aimed at applying the IUCN category system to the Baekdudaegan Protected Area. A classification key was developed to apply the system to the overlapped designated protected areas inside of Baekdudaegan Protected Area. Korea national parks and forests managers' and experts' opinions were collected and they all agreed to the use of multiple classification in Baekdudaegan Protected Area. For example, the type of natural forests among the Forest Genetic Resources Reserves was classified to be IUCN Category Ia while other types of Forest Genetic Resources Reserve was classified to be Category IV. And the Protected Forest Landscape was classified to be Category V while the other types of protected forests were classified to be Category VI. The study suggests the need of classification of forest protected areas including Baekdudaegan Protected Area using IUCN system accompanying with protected areas management effectiveness evaluation.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.501-508
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• 2020

His paper looks more closely at the Republic of Korea's (ROK) Navy submarine berth-allocation strategies, with the study's results ultimately resulting in the proposition of an integer programming model. Current submarine berth-allocation planning problems include the need for more minimal berth-shifting and general support service failures, as a lack of efficient submarine berth-allocation often leads to submarines unable to receive the support service they need due to the inadequacy of their assigned berths. Currently, the ROK Navy allocates berths by only taking available reserve resources and the full-capacity limits of support services into account. This paper expands upon this strategy, and proposes a model which would allow for submarine berth allocation planning to also take submarine support service scheduling into account, allowing for more efficient and timely submarine servicing. This proposed model in turn minimizes berth shifting, support service failures, and allows for full coordination with the submarine support service request schedule. The construction of this model was carried out through data gathered on the ROK Navy's fleets and forces, allowing for a more nuanced analysis of existing issues with submarine berth-allocation planning.

• Journal of the Korea Society for Simulation
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• v.30 no.1
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• pp.31-42
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• 2021

In order to respond to the ballistic missile threat of North Korea, the ROK military is constructing a multi-layered defense that can minimize the vulnerability of single-layered defense. Accordingly, it is necessary to study an operation plan which can maximize the intercept rate of a multi-layered defense system. And to study the operation plan of the Korean missile defense system, it must be considered that the operational environment of the Korean military and the effects of the strategic strike system. Therefore, this study proposes a simulation model that reflects the characteristics of the Korean missile defense system and analyzes four interceptor missile operation plans. The simulation result indicates that a high intercept rate can be achieved in various situations by comprehensively considering the ballistic missile threat estimate, interceptor missile reserve, and the strategic strike system effect.

• Journal of Forest and Environmental Science
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• v.38 no.2
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• pp.90-101
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• 2022

The study aims to assess composition, diversity and population indices of natural regeneration of woody species in Jebel El Gerrie forest reserve, Blue Nile State, Sudan. We conducted field work between December 2018 and January 2019. We used random sampling to collect vegetation data in the forest where we made a total of 90 circular sample plots (radius 17.84 m) and distributed them proportionally to the area of each of the four density-based vegetation classes of the forest i.e. high density (C1), medium density (C2), low density (C3) and crop land (C4). In each sample plot we identified all regenerating tree species and counted their regeneration frequencies. We calculated ecological metrics of regeneration frequency, density, abundance, richness, evenness, diversity and importance value index (IVI) and drew abundance rank curve. Results revealed that out of fifteen mature tree species present, natural regeneration of 8 species, which belong to 6 families, was observed. The relatively most frequently naturally regenerating and abundant species were Anogeissus leiocarpa and Combretum hartmannianum. Richness, evenness and diversity of regenerating species were 1.33, 0.82 and 1.7, respectively. One-way ANOVA (α=0.05) of mean regeneration densities disclosed that there were significant differences (F_3,86=16.77, p=0.000) between C2 & C3 (p=0.000) and C2 & C4 (p=0.000). While regeneration of seven tree species were absent, two, two and four species were of good, poor and fair regeneration status, respectively. A comparison of mean density of natural regeneration with that of parent trees reflects a poor regeneration status of the forest. The study provides empirical results on the regeneration status of species and signifies the need for management interventions for species conservation and restoration, maintenance of biodiversity and sustainable production.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.4
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• pp.377-385
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• 2022

Thermal batteries are specialized as primary reserve batteries that operate when the internal heat source is ignited and the produced heat (450~550℃) melts the initially insulating salt into highly conductive eutectic electrolyte. The heat source is composed of Fe powder and KClO₄ with different mass ratios and is inserted in-between the cells (stacks) to allow homogeneous heat transfer and ensure complete melting of the electrolyte. An ideal heat source has following criteria to satisfy: sufficient mechanical durability for stacking, appropriate heat calories, ease of combustion by an igniter, stable combustion rate, and modest peak temperature. To satisfy the aforementioned requirements, Fe powder must have high surface area and porosity to increase the reaction rate. Herein, the hydrothermal and spray drying synthesis techniques for Fe powder samples are employed to investigate the physicochemical properties of Fe powder samples and their applicability as a heat source constituent. The direct comparison with the state-of-the-art Fe powder is made to confirm the validity of synthesized products. Finally, the actual batteries were made with the synthesized iron powder samples to examine their performances during the battery operation.

• Journal of Forest and Environmental Science
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• v.38 no.3
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• pp.174-183
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• 2022

The study aims to examine population indices of mature trees in Jebel Elgarrie forest, Blue Nile State, Sudan. We used remote sensing techniques to stratify the forest into vegetation classes depending on tree density. We distributed 97 circular sample plots (0.1 ha) proportionally to the area of the vegetation classes. In each sample plot we identified, counted and recorded all mature trees (DBH ≥10 cm). We calculated frequency, density, abundance, richness, evenness and diversity for each species and we drew abundance rank curve of mature trees. We used One-Way ANOVA to test for differences (α=0.05) in mean density (No./ha) of mature trees between vegetation classes. Results revealed that the forest was conveniently sub-divided into high density (C1), medium density (C2), low density (C3) and bare farm land (C4) classes. We identified fifteen tree species that belong to 10 families and 14 genera. Combretaceae and Fabaceae were the common families while Anogeissus leiocarpa was the most frequently occurring species. While species diversity varied between vegetation classes, diversity of the forest as a whole is low. While mean density of mature trees in C1, C2, C3 and C4 it was 100, 74, 10, and 0, respectively, it was 54 for the whole forest indicating low stocking, Following One-Way ANOVA, multiple comparisons revealed significant differences in mean density of mature trees between C1 & C3 and C2 & C3. The study provided empirical results on population indices of mature tree species, which would be of importance for successful management and conservation of the forest.

• Smart Structures and Systems
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• v.29 no.6
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• pp.757-766
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• 2022

To train deep learning algorithms, a sufficient number of data are required. However, in most engineering systems, the acquisition of fault data is difficult or sometimes not feasible, while normal data are secured. The dearth of data is one of the major challenges to developing deep learning models, and fault diagnosis in particular cannot be made in the absence of fault data. With this context, this paper proposes an anomaly detection methodology for rotating machines using only normal data with self-labeling. Since only normal data are used for anomaly detection, a self-labeling method is used to generate a new labeled dataset. The overall procedure includes the following three steps: (1) transformation of normal data to self-labeled data based on a pretext task, (2) training the convolutional neural networks (CNN), and (3) anomaly detection using defined anomaly score based on the softmax output of the trained CNN. The softmax value of the abnormal sample shows different behavior from the normal softmax values. To verify the proposed method, four case studies were conducted, on the Case Western Reserve University (CWRU) bearing dataset, IEEE PHM 2012 data challenge dataset, PHMAP 2021 data challenge dataset, and laboratory bearing testbed; and the results were compared to those of existing machine learning and deep learning methods. The results showed that the proposed algorithm could detect faults in the bearing testbed and compressor with over 99.7% accuracy. In particular, it was possible to detect not only bearing faults but also structural faults such as unbalance and belt looseness with very high accuracy. Compared with the existing GAN, the autoencoder-based anomaly detection algorithm, the proposed method showed high anomaly detection performance.