• Journal of Information Processing Systems
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• v.10 no.4
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• pp.602-617
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• 2014

The performance of a cognitive radio network (CRN) solely depends on how precisely the secondary users can sense the presence or absence of primary users. The incorporation of a spatial false alarm makes deriving the probability of a correct decision a cumbersome task. Previous literature performed this task for the case of a received signal under a Normal probability density function case. In this paper we enhance the previous work, including the impact of carrier frequency, the gain of antennas on both sides, and antenna heights so as to observe the robustness against noise and interference and to make the correct decision of detection. Three small scale fading channels: Rayleigh, Normal, and Weibull were considered to get the real scenario of a CRN in an urban area. The incorporation of a maximal-ratio combining and selection combing with a variation of the number of received antennas have also been studied in order to achieve the correct decision of spectral sensing, so as to serve the cognitive users. Finally, we applied the above concept to a traffic model of the CRN, which we based on a two-dimensional state transition chain.

• 대한공업교육학회지
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• v.39 no.2
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• pp.1-18
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• 2014

This study took existing invention intellectual property related textbooks being utilized in secondary vocational education, analyzed the formation status of 'key learning elements' reflection ratio and drew optimum key learning elements formation ratio by invention intellectual property education content required in secondary vocational education in the future. For this, the study task was set up as 'what kind and how much of invention intellectual property key learning elements are in the invention intellectual property textbook education content now and what is the desirable ratio of each key learning elements in the future'. To resolve this task, 3 specialists analyzed the invention intellectual property education content reflection status and optimum reflection ratio by invention intellectual property education content required in the future is suggested by Delphi survey. The results of this study are as following. First, the result of analysis on invention intellectual property key learning elements included in the invention patent recognition books being utilized in secondary vocational education was that the books included all key learning elements; however, some textbooks have the trend of concentrating in D area (problem-solving activities). Second, the result of analysis on the reflection ratio by invention intellectual property education content area in the invention patent recognition books being utilized in secondary vocational education was that there was the trend in most textbooks that they concentrate in intellectual property creation area; while some textbooks deal with intellectual property protection area and intellectual property utilization area. Regarding by achievement type, knowledge area was main in all textbooks. Meanwhile, function area is dealt in invention patent basic, invention and problem-solving and design textbooks. Attitude area is not dealt or is dealt insufficiently in most textbooks. Third, the optimum reflection ratio of invention intellectual property education key learning elements required in secondary vocational education in the future as obtained by specialists' delphi survey was that it is necessary to decrease D (problem-solving activities) 17.7% area, E(invention fusion knowledge) 2.9% area, K(patent application) 6.9% and L(patent information investigation) area 9.6%. Regarding the optimum reflection ratio of invention intellectual property education content, it is suggested that the invention literacy area 3.1%, intellectual property creation area 4.5% and intellectual property protection area 10.6% would be decreased; while intellectual property utilization area 17.7% would be increased. Regarding optimum reflection ratio of achievement type, it is suggested that knowledge area 52% would be decreased; while function area 32.3% and attitude area 19.6% would be increased.

• Journal of The Korean Association For Science Education
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• v.16 no.2
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• pp.217-225
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• 1996

Science-related attitudes, perceptions of science classroom environments, and their relationships were investigated for a sample of 535 primary and secondary school students. Two scales of the Test of Science-Related Attitudes and five scales of the Classroom Environment Scale(CES) were administered. Students' perceptions of preferred science classroom environments were also investigated using the same scales of the CES and compared with those of actual classroom environments. The results indicated the primary school students had the most positive attitudes on Enjoyment of Science Lesson and Career Interest in Science. They also had the highest scores on perceptions of actual classroom environments, while the high school students had the lowest scores. Regarding the relationships between science-related attitudes and perceptions of classroom environments, multiple correlations for the five scales of the CES were found to be significant(p<01). The scores of four scales-Involvement, Teacher Support, Order and Organization, Rule Clarity-are significantly correlated with the scores of Enjoyment of Science Lesson. Students' perceptions of preferred classroom environments on the four scales of the CES are significantly higher than those in actual environments. However, students' perceptions of actual environments on Task Orientation are similar to those of preferred environments, and are not significantly correlated with Enjoyment of Science Lesson. Educational implications are discussed.

• Journal of Communications and Networks
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• v.17 no.4
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• pp.406-418
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• 2015

Cognitive radio networks (CRNs) have emerged as a promising solution to the problem of spectrum under utilization and artificial radio spectrum scarcity. The paradigm of dynamic spectrum access allows a secondary network comprising of secondary users (SUs) to coexist with a primary network comprising of licensed primary users (PUs) subject to the condition that SUs do not cause any interference to the primary network. Since it is necessary for SUs to avoid any interference to the primary network, PU activity precludes attempts of SUs to access the licensed spectrum and forces frequent channel switching for SUs. This dynamic nature of CRNs, coupled with the possibility that an SU may not share a common channel with all its neighbors, makes the task of multicast routing especially challenging. In this work, we have proposed a novel multipath on-demand multicast routing protocol for CRNs. The approach of multipath routing, although commonly used in unicast routing, has not been explored for multicasting earlier. Motivated by the fact that CRNs have highly dynamic conditions, whose parameters are often unknown, the multicast routing problem is modeled in the reinforcement learning based framework of learning automata. Simulation results demonstrate that the approach of multipath multicasting is feasible, with our proposed protocol showing a superior performance to a baseline state-of-the-art CRN multicasting protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.321-344
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• 2017

Smart homes are the new generation of homes where pervasive computing is employed to make the lives of the residents more convenient. Human activity recognition (HAR) is a fundamental task in these environments. Since critical decisions will be made based on HAR results, accurate recognition of human activities with low uncertainty is of crucial importance. In this paper, a novel HAR method based on a difference of convex programming (DCP) problem is represented, which manages to handle uncertainty. For this purpose, given an input sensor data stream, a primary belief in each activity is calculated for the sensor events. Since the primary beliefs are calculated based on some abstractions, they naturally bear an amount of uncertainty. To mitigate the effect of the uncertainty, a DCP problem is defined and solved to yield secondary beliefs. In this procedure, the uncertainty stemming from a sensor event is alleviated by its neighboring sensor events in the input stream. The final activity inference is based on the secondary beliefs. The proposed method is evaluated using a well-known and publicly available dataset. It is compared to four HAR schemes, which are based on temporal probabilistic graphical models, and a convex optimization-based HAR procedure, as benchmarks. The proposed method outperforms the benchmarks, having an acceptable accuracy of 82.61%, and an average F-measure of 82.3%.

• Journal of Educational Research in Mathematics
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• v.23 no.3
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• pp.353-371
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• 2013

The purpose of this study is to investigate preservice secondary teachers' understanding and modification capacity of tasks from mathematics textbooks. This study conducted a survey about how preservice teachers understand the features of mathematical tasks and how they would select and modify tasks appropriately from the curriculum and for lesson goals. The findings from the analysis suggest that the preservice teachers seem to recognize Procedures Without Connections tasks as the high-level tasks. Further, 43 percent of the total numbers appropriately selected the tasks from the curriculum and for lesson goals. Most of the preservice teachers appear to find it difficult to modify low-level tasks into high-level tasks.

• Journal of Science Education
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• v.34 no.2
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• pp.185-192
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• 2010

The purpose of this study was to develope the negative-emotion prediction model by hormonal changes during the scientific inquiry. For this study, biological classification task was developed that are suitable for comprehensive scientific inquiry. Forty-seven 2nd grade secondary school students (boy 18, girl 29) were participated in this study. The students are healthy for measure hormonal changes. The students performed the feathers classification task individually. Before and after the task, the strength of negative emotion was measured using adjective emotion check lists and they extracted their saliva sample for salivary hormone analysis. The results of this study, student's change of negative emotion during the feathers classification process was significant positive correlation(R=0.39, P<0.001) with student's salivary cortisol concentration. According to this results, we developed the negative emotion prediction model by salivary cortisol changes.

• Journal of Elementary Mathematics Education in Korea
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• v.23 no.1
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• pp.93-117
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• 2019

Considering precedent studies in which research subjects are mainly confined to secondary school students or higher grade students of elementary schools, we can notice that there has been implicit agreement that instruction of mathematical modeling is quite difficult to lower grade students of elementary schools. Compared to this tendency, this study aims to examine the possibility of instruction of mathematical modeling for all of school ages, and more specifically, the applicability of mathematical modeling tasks to lower graders. To do this, we developed a mathematical modeling task proper to cognitive characteristics of lower graders and applied this task to the second graders. Based on the research results by lesson observation and the teacher's reflection, some didactical suggestions were induced for teaching the lower grade elementary school students mathematical modeling.

• Cross-Cultural Studies
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• v.39
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• pp.329-354
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• 2015

The major goals of this paper are to identify the degree into which the meanings of 'see' verb can be extended, focusing on the extended meanings shown in the expressions that denote our instinctive actions for survival, such as eating or drinking, etc., and to clarify the doubt on whether any syntactic pattern can be associated with the meaning in the process of meaning extension of 'see' verb. For doing this task, this paper picked out 2,000 examples randomly from COCA (Corpus of Contemporary American English), in which the verb 'see' is used. This paper classified the sentences into thirteen different sentence types, according to the syntactic patterns. This research showed that these thirteen syntactic types lead us to figure out the process of the meaning extension of the verb 'see'. With this result, this paper made an attempt to provide the four steps toward the meaning extension of verb 'see'. The verb 'see' in the first step denotes the meaning of purely seeing the visualized objects. This verb in the second step expresses the shifted function, under which the agent in the subject position takes the seeing action as a secondary task in order to carry out other main task. The verb in the third step denotes the extended meanings irrelevant to the seeing action, because the sentences on this step do not contain any visualized objects. In the last step this verb functions as conventional implicature whose meaning does not contribute to the whole meaning of a sentence. In addition, this paper identified that the syntactic properties are deeply associated with the process of meaning extension of the verb 'see', and tried to formalize this relationship between the syntax and semantics within the framework of Construction Grammar based on A. Goldberg.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.22 no.1
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• pp.63-71
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• 2019

Purpose: The aim of this study was to identify the minimally meaningful dosage of inulin leading to a prebiotic effect in Indonesian infants. Methods: In a randomized controlled double-blinded, parallel, 3-arm intervention study, 164 healthy formula-fed infants aged 3 to 5 months first obtained formula-A (without inulin) during a 4-week adaptation period. Subsequently, 142 subjects were subjected to a 4-week feeding period by administering either formula-A (no inulin), formula-B (0.2 g/100 mL inulin) or formula-C (0.4 g/100 mL inulin). The primary outcome parameter was %-bifidobacteria in faecal samples determined using quantitative polymerase chain reaction analyses. Secondary outcome parameters were faecal %-lactobacilli, pH and stool frequency, and consistency. Growth and tolerance/adverse effects were recorded as safety parameters. Results: Typical %-bifidobacteria and %-lactobacilli at the end of the adaptation period in the study population were 14% and 2%, respectively. For faecal pH, significant differences between formula groups A vs. C and A vs. B were found at the end of the intervention period. Testing for differences in faecal %-bifidobacteria and %-lactobacilli between groups was hampered by non-normal data set distributions; no statistically significant differences were obtained. Comparisons within groups revealed that only in formula group C, all the three relevant parameters exhibited a significant effect with an increase in faecal %-bifidobacteria and %-lactobacilli and a decrease in pH. Conclusion: A consistent prebiotic effect along with a decrease in pH and increase in %-bifidobacteria and %-lactobacilli was found only in the group administered 0.4 g inulin/100 mL.