• Research in Mathematical Education
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• v.24 no.1
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• pp.1-27
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• 2021

For elementary school children, learning the standard multiplication algorithm with accuracy, clarity, consistency, and efficiency is a daunting task. Nonetheless, what should be our expectation in procedural fluency, for example, in finding the product of 25 and 37 among fifth grade students? Collectively, has the mathematics education community emphasized the value of conceptual understanding to the detriment of procedural fluency? In addition to examining these questions, we survey multiplication algorithms throughout history and in textbooks and reconceptualize the standard multiplication algorithm by using a new tool called the Multiplication Aid Template.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.334-337
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• 2021

Recently, the necessity of rapid response to social problems such as disasters and quarantine arising from the complex and diverse social structures has emerged. As the number of large buildings increases, large-scale human damage is expected in the event of a disaster such as fire. To solve this problem, efficient control must be achieved through interfacing with various equipment and facilities installed inside the building. In this paper, we intend to study the interface method for various facilities in the building for efficient control. In detail, the facility standard model is defined by examining the status and specification of building. In addition, we intend to design and propose a standard facility communication data frame to support the protocol applicable to this model.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.9
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• pp.1097-1105
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• 2017

This study examined how much chicken meat was in sausage made with pork. Both real-time polymerase chain reaction (PCR) and internal standard addition were used. Fifty ng of chicken DNA was added to the sausages as an internal standard. The addition of standard DNA increased the amplification efficiency of PCR and confirmed the possibility of quantitative analysis. A QIAamp DNA Micro Kit was used to improve the DNA recovery and amplification efficiency. The density of template DNA and primer were suitable for $3.0{\sim}5.0{\mu}L$ and $0.5{\mu}L$, respectively. Each DNA of pig and chicken was diluted in 10-fold from steps 50 ng to 0.05 ng. The detection limit of both pig and chicken meat was more than 0.05 ng and the correlation coefficient of the standard curve was at least 0.98. The result of the quantitative analysis after heat treatment of 3 samples of pigs and chickens mixed at 70:30 showed a 5.7% difference (64.3:35.7) between the expected value and measured value. The quantitative value was changed by affecting the DNA according to the heat treatment ($70^{\circ}C$, 10 min). An analysis of the pork and chicken content in sausages showed that it was difficult to detect chicken meat and the quantitative value of DNA according to the Ct value was very low. On the other hand, when adding standard material (50 ng of chicken DNA) to the sausages, the Ct value decreased gradually with increasing chicken mixing ratio. Thus, the mixing ratio of chicken in sausages could be estimated.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.1
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• pp.60-70
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• 2013

This study focused on analyzing classification system, technique methods, quality levels of periodic amendment characteristics in planting of standard specification. Through analyzing the above and comparing with foreign case study, this study suggests the improvement directions. The results improvement directions are as follows. 1. Many kinds of new construction were set up through the amendments of Landscape Standard Specification, but there are still needs to combine some construction categories because of mismatches between upper and lower categories. 2. Although the Landscape Standard Specification was revised to be more concrete, the contents there remains an ambiguous expression. So, standard specification is needed to revise a depth of earth ball or strength of support materials and quantify collect period of topsoil and application time. In addition, standards about following supervisor's instruction should be more detailed or deleted. 3. The standard specification has not been specified despite enactment and amendments reflecting the periodical paradigm and the needs of users, so it is still needed to revise. In addition, quality levels, planting periods, size of earth ball and performance criteria of tree materials are needed to revise. Each specific classification and construction methods were made by amendments of standard specification, but some standards are not clear and concrete. Therefore, the standard specification is needed to revise the classification system, technique methods, and problem deduction of quality levels and proposal of improvement. This study will be reference material when Landscape Standard Specification is revised.

• Journal of KIBIM
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• v.10 no.1
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• pp.9-22
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• 2020

Recently, BIM has been extended to infrastructures such as roads and bridges, and the demand for BIM standard development for ports is increasing internationally. Due to the low level of utilization of classification system and drawing standards compared to other infrastructures, and the closed nature of national security facilities, ports have insufficient level of connection and sharing environment among external systems or users. In addition, since the standardization of data for port facilities is not made, it is still necessary to establish an independent DB for each system and to ensure interoperability of data between these systems since it does not have a shared environment among similar data. Therefore, the purpose of this study is to develop and verify IFC, the international standard for BIM, in order to cope with the BIM environment and to be commonly used in the design, construction, and maintenance of port facilities. To this end, we build a standard schema with port-specific Express Notation according to buildingSMART International's standard development methodology. First, domestic and international reference model standards were analyzed to derive components such as space and facilities of port facilities. Based on this, the components of the port facility were derived through the codification, categorization, and normalization process developed by the research team. This was extended based on the port BIM object classification system developed by the research team. Normalization results were verified by designers and associations. Then, IFC schema construction was based on Express-G data modeling based on IFC 4 * 2 Candidate, which is a bridge candidate standard based on IFC4 (ISO16739), and IFC 4 * 3 Draft, which is developed by buildingSMART International. The final schema was validated using the commercialized validation tool. In addition, in order to verify the structural verification of the port IFC schema, the transformation process was verified by converting the caisson model into a Part21 file. In the future, this result will not only be used as a delivery standard for port BIM products, but will also be applied as a linkage standard between systems and a common data format for port BIM platforms when BIM is used in the maintenance phase. In particular, it is expected to be used as a core standard for data exchange in the port maintenance stage.

• Korean Journal of Pharmacognosy
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• v.17 no.1
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• pp.1-6
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• 1986

A cardiac principle of Aconiti tuber, higenamine was analyzed with a differential pluse voltammetry employing a glassy carbon electrode. The peak potentials for the oxidation of higenamine were varied depending on the pH of the media. Higenamine at the concentration of $5.4{\times}10^{-7}M$ (0.146ppm) was easily determined using a pH 7.0 phosphate buffer. The amounts of higenamine in the crude Aconiti tuber and tablets containing A. tuber were determined by a standard addition method after extracting with methanol, partitioning with a mixture of $H_2O$ and $CHCl_3$, and freeze-drying the aqueous layer.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.113-114
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• 2017

Recently, Subway workers have died from lung cancer. According to the Epidemiological Survey of the Welfare Corporation Institute of Pulmonary Disease of the Welfare Corporation, the family members applied for industrial accidents. The radon concentration in the subway work area was found to exceed 10 times the recommended standard value of 148 becquerels (Bq/㎥) in domestic multipurpose facilities. In addition, as a result of the national indoor radon concentration survey conducted by the Ministry of Environment in 2010 and 2013, housing was found to be over 100 becquerels (Bq/㎥) in 41% of the surveyed subjects. In addition, it was found that in 2012, 16.3% of villages exceeded the radon standard value in the survey on natural radioactive materials containing groundwater.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.2
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• pp.64-69
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• 2013

The structure of pore network of gas diffusion layers (GDLs) in PEMFCs plays a critical role in determining the transport phenomena of reaction gas as well as generated water. In addition, the interactive characteristics between water and surface of pore are no less important than the structural characteristics of pore network. In this study, porometric investigation is conducted for two kinds of GDL using method of standard porosimetry which enable to distinguish hydrophobic pores from hydrophilic pores of GDLs. The porosity of TGPH-120 decreases by 6% by adding 30 wt.% of PTFE, but the porosity of hydrophilic pores decreases by 12%. The relation of $p_c-S_{nw}$ varies with the addition of PTFE, especially at low $p_c$.

• Journal of Korean Library and Information Science Society
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• v.44 no.4
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• pp.233-254
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• 2013

Collecting terms in thesaurus construction work is the most difficult. A dictionary is thesaurus can be used as an excellent term acquisition. Reflect faithfully the provisions of Korean literary "Standard Korean Dictionary" is a standard dictionary of the Korea. The "Standard Korean Dictionary" is simply the definition of entry, as well as a wide range of information about the term because it contains a systematic, it can be used to build a thesaurus. In this study, the "Standard Korean Dictionary" has the relevant information using a variety of terms, it is defined as the thesaurus term relationship. In addition, the separation of the term, equal relationships and hierarchical set of relationships, the use of qualifiers, North Korean issues, the issue presented in thesaurus construction, and suggest ways to solve the problem.

• Journal of Food Hygiene and Safety
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• v.24 no.4
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• pp.348-351
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• 2009

This study was designed to estimate the effect of ethanol addition on shelf-life extension and changes in growth of total aerobic bacteria in fresh wet noodles. The wet noodle was made with addition of 0, 1 and 2% ethanol. During the storage at $10^{\circ}C$, wet noodles were monitored changes in the total numbers of aerobic bacteria. A 6 log cfu/g was applied as a standard for microbiological quality of foods. As a result, the shelf-lifes of wet noodle with addition of ethanol at the standard were 9.17 days at no ethanol, 15.02 days at 1% ethanol and 27.03 days at 2% ethanol. The respective percentage increases in the shelf-life observed at both 1 and 2% ethanol addition were 63.8% and 194.8% comparing with no ethanol treatment. Consequently, addition of ethanol into fresh wet noodle inhibited growth of total aerobic bacteria and extended shelf-life.