• Communications of the Korean Mathematical Society
• /
• v.25 no.1
• /
• pp.19-25
• /
• 2010

$3{\times}3{\times}3$ is the meaningful smallest product of three chains of each size 2n+1 since $1{\times}1{\times}1$ is a 1-element poset. The linear discrepancy of the product of three chains $2n{\times}2n{\times}2n$ is found as $6n^3-2n^2-1$. But the case of the product of three chains $(2n + 1){\times}(2n + 1){\times}(2n + 1)$ is not known yet. In this paper, we determine ld$(3{\times}3{\times}3)$ as a case to determine the linear discrepancy of the product of three chains of each size 2n + 1.

• Kyungpook Mathematical Journal
• /
• v.60 no.1
• /
• pp.1-20
• /
• 2020

A simple but elegant result of Rival states that every sublattice L of a finite distributive lattice 𝒫 can be constructed from 𝒫 by removing a particular family 𝒥_L of its irreducible intervals. Applying this in the case that 𝒫 is a product of a finite set 𝒞 of chains, we get a one-to-one correspondence L ↦ 𝒟_𝒫(L) between the sublattices of 𝒫 and the preorders spanned by a canonical sublattice 𝒞^⋄ of 𝒫. We then show that L is a tight sublattice of the product of chains 𝒫 if and only if 𝒟_𝒫(L) is asymmetric. This yields a one-to-one correspondence between the tight sublattices of 𝒫 and the posets spanned by its poset J(𝒫) of non-zero join-irreducible elements. With this we recover and extend, among other classical results, the correspondence derived from results of Birkhoff and Dilworth, between the tight embeddings of a finite distributive lattice L into products of chains, and the chain decompositions of its poset J(L) of non-zero join-irreducible elements.

• Journal of Computational Design and Engineering
• /
• v.3 no.1
• /
• pp.53-62
• /
• 2016

The current trends of product customization and repair of high value parts with individual defects demand automation and a high degree of flexibility of the involved manufacturing process chains. To determine the corresponding requirements this paper gives an overview of manufacturing process chains by distinguishing between horizontal and vertical process chains. The established way of modeling and programming processes with CAx systems and existing approaches is shown. Furthermore, the different types of possible adaptions of a manufacturing process chain are shown and considered as a cascaded control loop. Following this it is discussed which key requirements of repair process chains are unresolved by existing approaches. To overcome the deficits this paper introduces repair features which comprise the idea of geometric features and defines analytical auxiliary geometries based on the measurement input data. This meets challenges normally caused by working directly on reconstructed geometries in the form of triangulated surfaces which are prone to artifacts. Embedded into function blocks, this allows the use of traditional approaches for manufacturing process chains to be applied to adaptive repair process chains.

• The korean journal of orthodontics
• /
• v.48 no.6
• /
• pp.384-394
• /
• 2018

Objective: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. Methods: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200% of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. Results: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200% of the original length. Conclusions: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.9
• /
• pp.333-340
• /
• 2021

In Vietnam, the desire to consume organic vegetables is increasing as people become increasingly concerned about foods that contain several chemicals and toxins that are hazardous to their health. However, numerous subjective and objective factors continue to influence customers' purchase intention and behavior, indicating that this market has not yet reached its full potential. The study analyzes the impacts of trust, price, and convenience on consumers' consumption behavior and frequency of using organic vegetables in Northern Vietnam. We surveyed 312 consumers in the region. After classifying the data, 178 participants have used or regularly used organic vegetables selected for further study. Next, the author applied SmartPLS software with version 3.3 to test the hypotheses and analyze the effects of the observations. The result shows that three main factors affect customers' organic vegetable consumption behavior, especially perceived convenience. This study contributes to the development of comprehensive policy mechanisms and regulations on product traceability. Furthermore, market management authorities must have a strategy in place to inspect the product quality of organic vegetable store chains regularly to build customer trust and support the growth of organic vegetable production and supply chains in Vietnam's northern region.

• Industrial Engineering and Management Systems
• /
• v.15 no.2
• /
• pp.156-172
• /
• 2016

Complex and uncertain issues in supply chain result in integrated decision making processes in supply chains. So decentralized (distributed) decision making (DDM) approach is considered as a crucial stage in supply chain planning. In this paper, an uncertain DDM through coordination mechanism is addressed for a multi-product supply chain planning problem. The main concern of this study is comparison of DDM approach with centralized decision making (CDM) approach while some parameters of decision making are assumed to be uncertain. The uncertain DDM problem is modeled through fuzzy mathematical programming in which products' demands are assumed to be uncertain and modeled using fuzzy sets. Moreover, a CDM approach is customized and developed in presence of fuzzy parameters. Both approaches are solved using three fuzzy mathematical optimization methods. Hence, the contribution of this paper can be summarized as follows: 1) proposing a DDM approach for a multi-product supply chain planning problem; 2) Introducing a coordination mechanism in the proposed DDM approach in order to utilize the benefits of a CDM approach while using DDM approach; 3) Modeling the aforementioned problem through fuzzy mathematical programming; 4) Comparing the performance of proposed DDM and a customized uncertain CDM approach on multi-product supply chain planning; 5) Applying three fuzzy mathematical optimization methods in order to address and compare the performance of both DDM and CDM approaches. The results of these fuzzy optimization methods are compared. Computational results illustrate that the proposed DDM approach closely approximates the optimal solutions generated by the CDM approach while the manufacturer's and retailers' decisions are optimized through a coordination mechanism making lasting relationship.

• Industrial Engineering and Management Systems
• /
• v.12 no.4
• /
• pp.317-329
• /
• 2013

In recent years, for the purpose of solving the problem regarding environment protection and resource saving, certain measures and policies have been promoted to establish a green supply chains (GSC) with material flows from collection of used products to reuse of recycled parts in production of products. In this study, we propose an optimal operation of the GSC while considering the collection incentive of the used products and quality for recycling of used products. Two types of decision-making approaches are used for product quantity, collection incentive of used products and lower limit of quality level of reusable parts in the used products for recycling in the GSC. One is the decision-making under an independent policy in decentralized supply chains where a retailer and a manufacturer make decisions so as to maximize profits individually. The other is the decision-making under a cooperative policy in centralized supply chains where a retailer and a manufacturer make decisions cooperatively so as to maximize the whole system's profit. Additionally, we also discuss supply chain coordination as a manufacturer-retailer partnership based on profit sharing. Furthermore, we show the effect of the quality of the reusable parts on the optimal decisions. The collection incentive of the used products was found to bring more profitability to the GSC activity.

• Journal of Distribution Science
• /
• v.18 no.4
• /
• pp.97-106
• /
• 2020

Purpose: Participation of firms in Global Value Chains (GVC) has contributed significantly to the improvement of economic outcomes for firms in developing countries. However, evidence suggests that these economic outcomes are gained at the cost of labourers' poor working conditions. This research contributes to existing literature on GVCs by investigating the influence of different governance structures on economic and social upgrading of firms participating in GVCs. Furthermore, the research attempts to understand the relationship between economic and social upgrading in GVCs. Research design and methodology: Detailed qualitative primary research was carried out in the football industry of Sialkot, Pakistan. The case study approach was employed, and football firms were the unit of analysis. Semi-structured interviews with firms' representatives were conducted. Results: Findings reveal that most firms were found in captive, relational and market governance structures. Furthermore, product and process upgrading were witnessed in all firms; however, social upgrading was observed mostly in captive and relational GVCs. Moreover, social upgrading was linked to economic upgrading in captive and relational networks. Conclusions: The findings from the Sialkot football industry reflect that buyers pay higher prices and margins to their suppliers once they upgrade their products and processes.

• Bulletin of the Korean Mathematical Society
• /
• v.42 no.2
• /
• pp.315-326
• /
• 2005

In this paper, we define the weak dimension and the chain-weak dimension of an ordered set by using weak orders and chain-weak orders, respectively, as realizers. First, we prove that if P is not a weak order, then the weak dimension of P is the same as the dimension of P. Next, we determine the chain-weak dimension of the product of k-element chains. Finally, we prove some properties of chain-weak dimension which hold for dimension.

• Journal of Korean Society for Quality Management
• /
• v.37 no.1
• /
• pp.69-79
• /
• 2009

Supply Chain Management is the process of planning, implementing and controlling the operations of the supply chain to satisfy customer requirements as efficiently as possible. It spans all movements and storage of raw materials, work-in-process inventory, and finished goods from point-of-origin to point-of-consumption. Korean Standards Association claims the Supply Chain Quality Management(SCQM) as a win-win model of organizations among the supply chains for the best product/service quality to final customers. The SCQM is focused on quality of product/service and will do much for improving manufacturing performance between customer and suppliers. Consulting-teams make every effort to design suitable solution for constructing solutions and improving the performance. This study is to analyze the performance of SCQM consulting, from July of 2007 to June of 2008, and would provide some guidelines to design the optimal consulting models and develop guidebooks.