• Journal of Elementary Mathematics Education in Korea
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• v.23 no.1
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• pp.143-168
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• 2019

Along with the significance of algebraic thinking in elementary school, it has been recently emphasized that the properties of number and operations need to be explored in a meaningful way rather than in an implicit way. Given this, the purpose of this study was to analyze how third graders could understand the properties of operations in multiplication after they were taught such properties through a reconstructed unit of multiplication. For this purpose, the students from three classes participated in this study and they completed pre-test and post-test of the properties of operations in multiplication. The results of this study showed that in the post-test most students were able to employ the associative property, commutative property, and distributive property of multiplication in (two digits) × (one digit) and were successful in applying such properties in (two digits) × (two digits). Some students also refined their explanation by generalizing computational properties. This paper closes with some implications on how to teach computational properties in elementary mathematics.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.1033-1047
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• 2017

Traditional explicit authentication, which requires awareness of the user's authentication process, is a burden on the user, which is one of main reasons why users tend not to employ authentication. In this paper, we try to reduce such cost by employing implicit authentication methods, such as biometrics and location based authentication methods. We define the 4-level security assurance model, where each level is mapped to an explicit authentication method. We implement our model as an Android application, where the implicit authentication methods are touch-stroke dynamics-based, face recognition based, and the location based authentication. From user experiment, we could show that the authentication cost is reduced by 14.9% compared to password authentication-only case and by 21.7% compared to the case where 6-digit PIN authentication is solely used.

• The Transactions of the Korea Information Processing Society
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• v.3 no.3
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• pp.449-459
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• 1996

The main goal of this paper is to introduce a novel definition for fuzzy mathematical morphology and a neural network implementation. The generalized- mean operator plays the key role for the definition. Such definition is well suited for neural network implementation. The first stage of the shared-weight neural network has adequate architecture to perform morphological operation. The shared- weight network performs classification based on the features extracted with the fuzzy morphological operation defined in this paper. Therefore, the parameters for the fuzzy definition can be optimized using neural network learning paradigm. Learning rules for the structuring elements, degree of membership, and weighting factors are precisely described. In application to handwritten digit recognition problem, the fuzzy morphological shared-weight neural network produced the results which are comparable to the state-of art for this problem.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.642-648
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• 2011

Purpose: The recent advances in microsurgical techniques and their refinement over the past decade have greatly expanded the indications for digital replantations and have enabled us to salvage severed fingers more often. Many studies have reported greater than 80% viability rates in replantation surgery with functional results. However, replantation of multi-level amputations still remain a challenging problem and the decision of whether or not to replant an amputated part is difficult even for an experienced reconstructive surgeon because the ultimate functional result is unpredictable. Methods: Between January of 2002 and May of 2008, we treated 10 multi-level amputated digits of 7 patients. After brachial plexus block, meticulous replantation procedure was performed under microscopic magnification. Postoperatively, hand elevation, heat lamp, drug therapy and hyperbaric oxygen therapy were applied with careful observation of digital circulation. Early rehabilitation protocol was performed for functional improvement. Results: Among the 19 amputated segments of 10 digits, 16 segments survived completely without any complications. Overall survival rate was 84%. Complete necrosis of one finger tip segment and partial necrosis of two distal amputated segments developed and subsequent surgical interventions such as groin flap, local advancement flap and skin graft were performed. The overall result was functionally and aesthetically satisfactory. Conclusion: We experienced successful replantations of multi-level amputated digits. When we encounter a multi-level amputation, the key question is whether or not it is a contraindication to replantation. Despite the demand for skillful microsurgical technique and longer operative time, the authors' results prove it is worth attempting replantations in multi-level amputation because of the superiority in aesthetic and functional results.

• Journal of Preventive Medicine and Public Health
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• v.42 no.1
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• pp.35-41
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• 2009

Objectives : The changing population age structure and rapidly increasing medical costs make providing high-quality, effective medical care for the elderly a challenge. This study assessed the satisfaction with medical care in terms of comprehensiveness, general satisfaction, and accessibility among community-dwelling Korean elders. Methods : Data were obtained from a nationwide representative sample of the older adults(aged 65 years old or older) living in the community, who participated in a 2006 telephone survey conducted using random digit dialing(n=881). General satisfaction, comprehensiveness and accessibility were measured using a 10-item satisfaction survey questionnaire. Descriptive analysis was used to assess the distribution of each of three components of subjective satisfaction. Analysis of covariance(ANCOVA) was used to examine the association of each of the three components with socioeconomic variables. Results : Comprehensiveness and general satisfaction were low among older people with a high socioeconomic status. Accessibility was evaluated as low among older people of low socioeconomic status, those living in rural areas and those who were medical aid beneficiaries. Conclusions : Urgent interventions should be considered in order to improve accessibility to medical care for elders of low socioeconomic status and those living in rural communities. Given the rapid aging of the population, we need to develop a monitoring system to improve the quality of geriatric care.

• The Mathematical Education
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• v.40 no.2
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• pp.195-215
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• 2001

The purpose of this paper is to present a specific set of home teaching methods in hopes to prevent slow learner of the elementary mathematics. This paper deals with the number and operations, one of five topics in the elementary mathematics A survey of two hundred elementary school teachers was made to see the teacher's opinions of the role of home studying and to concretize the contents of the research topics. There were asked which is the most essential contents for the concrete loaming and which is the most difficult monad that might cause slow leaner. And those were found to be; counting, and arithmetic operations(addition and subtraction) of one or two-digit numbers and multiplication and their concepts representations and operations(addition and subtraction) of fractions. The home teaching methods are based on the situated learning about problem solving in real life situations and on the active teaming which induces children's participation in the process of teaching and learning. Those activities in teaching each contents are designed to deal with real objects and situations. Most teaching methods are presented in the order of school curriculum. To teach the concepts of numbers and the place value, useful activities using manipulative materials (Base ten blocks, Unifix, etc.) or real objects are also proposed. Natural number's operations such as addition, subtraction and multiplication are subdivided into small steps depending upon current curriculum, then for understanding of operational meaning and generalization, games and activities related to the calculation of changes are suggested. For fractions, this paper suggest 10 learning steps, say equivalent partition, fractional pattern, fractional size, relationship between the mixed fractions and the improper fraction, identifying fractions on the number line, 1 as a unit, discrete view point of fractions, comparison of fractional sizes, addition and subtraction, quantitative concepts. This research basically centers on the informal activities of kids under the real-life situation because such experiences are believed to be useful to prevent slow learner. All activities and learnings in this paper assume children's active participation and we believe that such active and informal learning would be more effective for learning transfer and generalization.

• Annals of Rehabilitation Medicine
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• v.41 no.6
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• pp.924-934
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• 2017

Objective To investigate the anatomical correlates of the neuropsychological deficits in patients with the cerebellar stroke. Methods We screened patients who were admitted to the National Rehabilitation Center with the cerebellar stroke between October 2012 and November 2016. The patients with the cerebellar stroke who underwent neuropsychological testing for which the Seoul Neuropsychological Screening Battery (SNSB) or the SNSB-II were enrolled. The neuropsychological function capacities were compared in accordance with the stroke type (hemorrhagic vs. ischemic) and the location (right/left anterior, right/left posterior intermediate, right/left posterior lateral lobe, and vermis). Mean z-scores were computed to compare the patient performances with the population averages. Results Twenty-six patients (15 with ischemic stroke and 11 with hemorrhagic stroke) with a mean age of $54.8{\pm}16.6$ years were assessed $8.8{\pm}9.2$ months after the stroke. Differences in the neuropsychological functioning according to the stroke type were not observed. All of the numerical subtests of the stroke patients showed significantly poorer performances compared with the population averages (mean z-score <0), and some of the subtests revealed abnormal performances in attention-, visuospatial function-, memory-, and frontal/executive function-related tasks (mean z-score <-1). The patients with the presence of a lesion in the right posterior intermediate lobe of the cerebellum showed a poorer performance in the subtests evaluating the executive function including the Korean-version Stroop Test (p=0.04), the Digit Symbol Coding Test (p=0.01), and the Korean-version Trail Making Test (p=0.02) compared with the patients without that lesion. Conclusion The present study confirms that the cerebellar stroke affects the neuropsychological functioning which is associated with the anatomical site of stroke.

• Journal of the Korea Convergence Society
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• v.12 no.12
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• pp.365-370
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• 2021

The current study aims to investigate the relationship between working memory capacity, vocabulary size, and listening competence of Korean EFL (English as a Foreign Language) learners. 30 English education majors from a university in Korea were recruited. The backward digit span and the operation span tasks were used to measure the participants' working memory capacity, while the Listening Vocabulary Level Test (LVLT) and the Michigan English Test (MET) were employed to measure their vocabulary size and listening proficiency in English, respectively. The correlational analyses revealed that the bigger one's working memory storage was, the better the person processed incoming input. However, no statistically significant correlation was found between working memory capacity, English vocabulary size, and listening proficiency, possibly due to the small sample size and the homogeneous subjects.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.95-102
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• 2019

This study was to investigate the effect of eye movement and intentional finger movement on cognitive ability. Normal adult subjects were randomly divided into two groups: saccadic eye movement(SEM) and intentional finger movement(IFM). After 2 weeks of intervention, Digit span was used for short-term memory test and N-back was used for working memory test. As a result, the short-term memory of the IFM group increased significantly over time, and the follow-up test showed difference between group. The IFM group's the execution time, the error count and the accuracy rate of n-back item showed significant effects over time. The SEM group's the execution time and the accuracy of n-back item showed significant effects over time. In conclusion, the IFM method, which is a multiple stimulus that can activate the cerebral cortex more extensively than the single stimulus SEM, may be more useful as an intervention method of cognitive function improvement.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.2
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• pp.85-101
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• 2021

This study aims to gain insight through understanding the Metaverse, which has recently become a hot topic. The study utilizes the methods of case study and News Bigdata Analysis Services. The Metaverse can be defined as a world with no separation between the virtual and real worlds. Currently, the Metaverse is dominated mainly by the MZ generation, but just like smartphones have quickly entered our lives, the Metaverse will soon, too, become a part of our lives. To follow up on this change, all companies, including global companies, are going after the Metaverse. Today, the Metaverse is successfully being used in all types of fields, including gaming, performing arts, business, etc., and its essential technologies include VR/AR/MR/XR and AI. This study intends to help understand the Metaverse through a case analysis of Zepeto, which has 200 million users worldwide. On Zepeto, users can decorate their own avatars, hang out with friends, go to art galleries and performances, and create and sell items. Of these users, 90% are from outside of South Korea, and 80% are teenagers. With most of the users being underage, many legal and social problems also follow. Nevertheless, who will be the first to conquer the new world of the Metaverse will continue to be a big issue. This study also analyzes domestic news articles about the Metaverse by utilizing the BigKinds system. Starting in 1996, the number of articles about the Metaverse each year remains single digit, until in 2020 when the number sharply rises to 86 news. As of June 2021, there are 1,663 articles on the Metaverse. This study suggests that the Metaverse should now be carefully examined and closely followed.