• Journal of the Microelectronics and Packaging Society
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• v.19 no.2
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• pp.7-15
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• 2012

Semiconductor packages are increasingly moving toward miniaturization, lighter and multi-functions for mobile application, which requires highly integrated multi-stack package. To meet the industrial demand, the package and silicon chip become thinner, and ultra-thin packages will show serious reliability problems such as warpage, crack and other failures. These problems are mainly caused by the mismatch of various package materials and geometric dimensions. In this study we perform the numerical analysis of the warpage deformation and thermal stress of 4-layer stacked FBGA package after EMC molding and reflow process, respectively. After EMC molding and reflow process, the package exhibits the different warpage characteristics due to the temperature-dependent material properties. Key material properties which affect the warpage of package are investigated such as the elastic moduli and CTEs of EMC and PCB. It is found that CTE of EMC material is the dominant factor which controls the warpage. The results of RSM optimization of the material properties demonstrate that warpage can be reduced by $28{\mu}m$. As the silicon die becomes thinner, the maximum stress of each die is increased. In particular, the stress of the top die is substantially increased at the outer edge of the die. This stress concentration will lead to the failure of the package. Therefore, proper selection of package material and structural design are essential for the ultra-thin die packages.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.227-227
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• 2015

The Wairarapa Valley occupies a predominantly rural area in the lower North Island of New Zealand. It supports a mix of intensive farming (dairy), dry stock farming (sheep and beef cattle) and horticulture (including wine grapes). The valley floor is traversed by the Ruamahanga River, the largest river in the Wellington region with a total catchment area of 3,430 km2. Environmental, cultural and recreational values associated with this Ruamahanga River are very high. The alluvial gravel and sand aquifers of the Wairarapa Valley, support productive groundwater aquifers at depths of up to 100 metres below ground while the Ruamahanga River and its tributaries present a further source of water for users. Water is allocated to users via resource consents by Greater Wellington Regional Council (GWRC). With intensifying land use, demand from the surface and groundwater resources of the Wairarapa Valley has increased substantially in recent times and careful management is needed to ensure values are maintained. This paper describes the approach being taken to manage water resources in the Wairarapa Valley and redefine appropriate limits of sustainable water use. There are three key parts: Quantifying the groundwater resource. A FEFLOW numerical groundwater flow model was developed by GWRC. This modelling phase provided a much improved understanding of aquifer recharge and abstraction processes. It also began to reveal the extent of hydraulic connection between aquifer and river systems and the importance of moving towards an integrated (conjunctive) approach to allocating water. Development of a conjunctive management framework. The FEFLOW model was used to quantify the stream flow depletion impacts of a range of groundwater abstraction scenarios. From this, three abstraction categories (A, B and C) that describe diminishing degrees of hydraulic connection between ground and surface water resources were mapped in 3 dimensions across the Valley. Interim allocation limits have been defined for each of 17 discrete management units within the valley based on both local scale aquifer recharge and stream flow depletion criteria but also cumulative impacts at the valley-wide scale. These allocation limits are to be further refined into agreed final limits through a community-led decision making process. Community involvement in the limit setting process. Historically in New Zealand, limits for sustainable resource use have been established primarily on the basis of 'hard science' and the decision making process has been driven by regional councils. Community involvement in limit setting processes has been through consultation rather than active participation. Recent legislation in the form of a National Policy Statement on Freshwater Management (2011) is reforming this approach. In particular, collaborative consensus-based decision making with active engagement from stakeholders is now expected. With this in mind, a committee of Wairarapa local people with a wide range of backgrounds was established in 2014. The role of this committee is to make final recommendations about resource use limits (including allocation of water) that reflect the aspirations of the communities they represent. To assist the committee in taking a holistic view it is intended that the existing numerical groundwater flow models will be coupled with with surface flow, contaminant transport, biological and economic models. This will provide the basis for assessing the likely outcomes of a range of future land use and resource limit scenarios.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.161-180
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• 2018

Environmental value is essential to the survival and development of humans. Environmental value and its importance are being emphasized, and related disputes are being expanded. The concept of green logistics is understood to be the same as that of the environment. As a way to preserve nature and engage in sustainable development, green logistics includes all logistical activities for protecting nature and minimizing or reducing behaviors that harm the environment for all processes, including using and reusing products and abolishing the search for resources by final users. All areas of human activity, such as the political, economic, social, and cultural sectors, strive to protect and preserve the environment and nature. In particular, the preservation of the environment shall be stressed in the economic activities that produce various products and expand the value added, and similarly for the social aspects. Green (environment) logistics aims to protect the environment and expand the prevention of environmental destruction and minimization on Earth. Some important cases and experiences that were introduced and applied in major countries are summarized. This research reviewed previous studies and the concepts of green logistics, including at ports, which represent a key sector of logistical activities. In this paper, air and water pollution at Incheon Port were investigated, and alternatives and system figures related to improving environmental logistics regarding three dimensions-country, company, and civil society-are recommended.

• The Mathematical Education
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• v.60 no.2
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• pp.173-190
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• 2021

Education for Sustainable Development is an imperative mean to achieve the sustainable development which is the key idea that meets the needs of both present and succeeding generations by reconciling environmental protection, social development and economic growth. This study addressed the following question. First, what is the overall structure of the ESD contents presented in the textbooks? Second, How are the sub-contents of ESD distributed in the textbooks? Lastly, How are the ESD contents connected to mathematics in the textbooks? For this purpose, the contents in the elemtentary mathematics textbooks from 1^st to 6^th grades were analyzed at both macro and micro levels through quantitative and qualitative research methods. As results, contents related to environmental, social, and economic dimensions were presented from the first grade. The contents were involved the mathematics content domains of Numbers and Operations, Data and Possibilities, and Patterns. However, the contents were presented intensively in middle and high grades, and environmental topics accounted for a high proportion. Among the activities related to ESD, many were focused on solving problems mathematically while some were presented to solve problems as well as to consider sustainability through the activities. Based on the results, the study aims to provide implications for the direction of mathematics education for sustainable development in elementary school.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.2
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• pp.171-182
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• 2022

The habitat degradation caused by large-scale reclamation leads to devastating impacts, such as fine sediment and mud shrimp Upogebia major settlement on Manila clam Ruditapes philippinarum aquaculture in the eastern Cheonsu Bay tidal flats, Republic of Korea. Despite these impacts, there is a lack of studies on the influence of fine sediments on tidal flats that constitute key mud shrimp habitats. This study provides information on the seawater-sediment environment and the influence of dissolved inorganic nitrogen (DIN) fluctuations depending on mud shrimp burrow hole density. Additionally, it discusses countermeasures for Manila clam habitat management. The results show that mean DIN effluxes in areas with a high-density of burrow holes were up to 4 times (0.12 mmol m^-2 d^-1) higher than those in sites of low-density (0.03 mmol m^-2 d^-1) within the Saho and Songhak-ri tidal flats. To manage interference within the competition zone of Songhak-ri tidal flat, it is important to utilize the settlements of spawning season in all three dimensions. Consequently, additional studies in other tidal flats are essential and research in zones where mud shrimps and juvenile clams coexist will help to determine the priorities in the efficient management of clam aquaculture.

• Journal of Korean Home Economics Education Association
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• v.32 no.4
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• pp.103-124
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• 2020

The purpose of this study was to develop and implement a home economics convergence education program applying problem-based learning method focusing on the middle school food and nutrition life unit, and verify the effect of this class on the problem-solving ability of students. For this, the study set up the theme of 'sustainable life' by examining the relationship with other subjects, and set the key question as 'what is the relationship with the environment of food resources, the influence of individual level, and the solution method?' was postulated. And developed the problem and the total of 8 classes. As a result of conducting the convergence education program with home economics applying problem-based learning method, the pre-test and post-test scores were 3,54 and 3.96, respectively, which showed a significant increase in problem-solving ability (p<.001). There were significant differences in the dimensions of problem-solving ability, except for problem clarification. Therefore, it was confirmed that the home economics and convergence education program applying problem-based learning method is an effective class for improving students' problem-solving ability.

• 한국노년학
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• v.27 no.2
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• pp.371-392
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• 2007

Marital status has drawn much attention as previous studies have been pointed it out as a key factor of health. Nonetheless, systematic studies on elderly marital status and health have been quite limited, for most researches have neglected the varying effects of marital status on health over the lifespan and mainly focused on midlife. This study, using nationwide survey on elderly population, attempts to discover the health differentials between widowed and married elderly and explain the differences though the structure and function of their social network. The results reveal that the magnitudes of marital status effects were differed by dimensions of health. The widowed were more likely to be unhappy than married, even after controlling the socio-demographic characteristics. In physical health, however, the health differences between widowed and married were less noticeable or disappeared, as sex, age and other structure factors were considered. Furthermore, the strength of social network factors affecting the physical and mental health of elderly turned out to be different between married and widowed: widowed were more likely than married to be affected by the contact with children and less likely to be affected by contact with friends/relatives. Such results had both positive and negative impact on physical and mental health of widowed. This may imply the difference in pathways of regulating health among the married and widowed elderly.

• Asia Marketing Journal
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• v.10 no.2
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• pp.99-123
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• 2008

Consumer satisfaction/dissatisfaction is key determinant of brand loyalty and store patronage behavior. But the results of many customer satisfaction surveys implemented by department stores show that consumer satisfactions do not predict the actual patronage behaviors well. The main reason of these surprising results would be that the consumer satisfaction indexes do not include some important determinants of consumer satisfaction. Many customer satisfaction surveys mainly focus on the evaluation of functional benefits including product assortments, merchandise prices and locational convenience. Recent studies indicate that emotional/hedonic benefits strongly influence the consumer satisfaction, intention to repurchase and intention to revisit. Our study suggests that both functional values and hedonic values should be included in developing the index of consumer satisfactions. The purpose of our study is to investigate the relationship between shopping value and consumer satisfaction, and actual patronage behavior. Shopping values is defined as the difference between total benefits and total shopping costs. Total benefits include the dimensions of product quality, service quality, and hedonic benefits. Total costs are classified as the monetary costs and non-monetary cost. The conceptual framework developed for this empirical study is as follows.

• Journal of Venture Innovation
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• v.6 no.3
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• pp.185-202
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• 2023

The COVID-19 pandemic catalyzed major changes in our work environment, underscoring the critical role of workplace flexibility. While a wealth of research exists on specific flexible work strategies and schedules, a broader understanding of workplace flexibility has been somewhat overlooked. This study aimed to bridge this gap by examining the correlation between workplace flexibility and organizational commitment. Our sample consisted of 300 employees from foreign businesses in the ICT(information and communications technology) service sector and the manufacturing industry, along with those from the top 50 leading Korean enterprises. We bifurcated workplace flexibility into two distinct categories for this study: quantitative and qualitative. Our results revealed that within the quantitative category, the flexibility of continuity of work and flexible place significantly enhanced organizational commitment. Interestingly, the flexibility of work schedules didn't have a marked impact on commitment levels. On the qualitative side, job autonomy and teamwork emerged as significant drivers of organizational commitment. It's worth noting that qualitative aspects of workplace flexibility had a more pronounced effect on organizational commitment than the quantitative elements. These findings highlight the necessity of approaching workplace flexibility from a comprehensive perspective, embracing both its quantitative and qualitative dimensions. For businesses aiming to maximize the benefits of flexibility, it's essential to cultivate a culture of open communication, champion collaboration, and prioritize job autonomy and teamwork. Establishing a work environment that actively supports feedback-oriented communication stands as a key component in this endeavor.

• The Mathematical Education
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• v.62 no.4
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• pp.531-549
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• 2023

Despite the significance of mathematics teacher guidebooks as a support for teacher learning, there are few studies that address how elementary mathematics teacher guidebooks support teacher learning. The purpose of this study was to analyze the educative features of elementary mathematics teacher guidebooks for grades 3 and 4. For this, six units from each of ten kinds of teacher guidebooks were analyzed in terms of seven dimensions of Teacher Learning Opportunities in Korean Mathematics Curriculum Materials (TLO-KMath). The results of this study showed that mathematics content knowledge for teaching was richly provided and well organized. Teacher guidebooks provided teacher knowledge to anticipate and understand student errors and misconceptions, but were not enough. Sample dialogues between a teacher and students were offered in the teacher guidebooks, making it easier for teachers to identify the overall lesson flow and key points of classroom discourse. Formative assessment was emphasized in the teacher guidebooks, including lesson-specific student responses and their concomitant feedback examples per main activity. Supplementary activities and worksheets were provided, but it lacked rationales for differentiated instruction in mathematics. Teacher knowledge of manipulative materials and technology use in mathematics was provided only in specific units and was generally insufficient. Teacher knowledge in building a mathematical community was mainly provided in terms of mathematical competency, mathematical classroom culture, and motivation. This paper finally presented implications for improving teacher guidebooks to actively support teacher learning.