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As a common transmission line, the microstrip line plays an important role in high-speed circuits. The purpose of this paper was to investigate the effects of the circuit design of microstrip lines on the signal integrity (SI). In addition, the influence of the type and thickness of the solder resist ink on SI was analyzed to provide guidance for the related producing process design of printed circuit boards (PCBs).

Microstrip line properties consisting of shape, line-width/line-space ratio, reference layer design and as-covered solder resist ink were designed to measure the insertion loss (S₂₁) in high-speed PCB.

The study showed that the insertion loss (S₂₁) of straight, meander, snake-shaped and wavy microstrip lines was approximately consistent. A microstrip line with width/space ratio less than 0.96 is necessary, as the differential line closing produces a mutual interference. Reference layer including the discontinuous area should be repaired by adjusting the microstrip line parameters. With regard to the solder resist ink, the insertion loss of novel solder resist ink decreased by 0.163 dB/in at 12.9 GHz and 0.164 dB/in at 14 GHz, compared with traditional solder resist ink. Accordingly, the insertion loss effectively improved at a lower thickness of solder resist.

This paper demonstrated that the common designing factors of line shape, line/space ratio, reference layer and solder resist influence microstrip line SI in the significant reference of designer-making PCB layout.

The purpose of this paper is to provide a knowledge-enabled digital twin for smart design (KDT-SD) of aircraft assembly line (AAL) to enhance the AAL efficiency, performance and visibility. Modern AALs usually need to have capabilities such as digital-physical interaction and self-evaluation that brings significant challenges to traditional design method for AAL. The digital twin (DT) combining with reusable knowledge, as the key technologies in this framework, is introduced to promote the design process by configuring, understanding and evaluating design scheme.

The proposed KDT-SD framework is designed with the introduction of DT and knowledge. First, dynamic design knowledge library (DDK-Lib) is established which could support the various activities of DT in the entire design process. Then, the knowledge-driven digital AAL modeling method is proposed. At last, knowledge-based smart evaluation is used to understand and identify the design flaws, which could further improvement of the design scheme.

By means of the KDT-SD framework proposed, it is possible to apply DT to reduce the complexity and discover design flaws in AAL design. Moreover, the knowledge equips DT with the capacities of rapid modeling and smart evaluation that improve design efficiency and quality.

The proposed KDT-SD framework can provide efficient design of AAL and evaluate the design performance in advance so that the feasibility of design scheme can be improved as much as possible.

The purpose of this paper is to develop a novel method for establishing the mathematical link between the restored Hogarth curve and the golden ratio, and to advance the potential application of the Hogarth curves in standardization of the garment pattern design by using this method.

The Hogarth curve was fully restored by using the plant design system (PDS) software package and divided the restored curve into two fragments based on the intersection point between the curve and the straight line joining the curve endpoints. The ratios between two fragments of curves and straight lines were calculated and compared with the golden ratio, respectively, which was set as a normalized value. The potential application of the restored Hogarth curves in the normalization of the garment pattern design was therefore studied by using the standard mannequins.

The ratio in the most beautiful curve, i.e., the fourth Hogarth curve, was found to be infinitely approaching to the golden ratio. Furthermore, the incorporation of the Hogarth curves into the garment pattern design demonstrated that the fourth Hogarth curve was the most aesthetic line.

This work offered a novel method for bridging the gaps between arts and maths, i.e., the mathematical relation between the Hogarth curves and the golden ratio. Such a method will provide the protocol to promote the potential applications of the Hogarth curves in the garment pattern design and the human body decoration.

This study seeks to present a simple assembly line design and its balance for a low‐volume manufacturing company.

The study presents experiences with the design and implementation of a simple assembly line. The implementation concerns three aspects; design and construction of the assembly line, the assembly analysis of the product, and then balancing of the line. It also discusses construction and implementation difficulties of this tactical tool in the case company.

The study presents some outcomes from the design, implementation, and balancing of an assembly line for SMEs.

The study is limited by the case company and its experience.

This study is not pure theoretical study, it has application stages for industry, and it provides some real interface for the people from SMEs.

The approach has an original value in respect of implementation of assembly line for a small manufacturing company which has many limitations.

Over the past decade two approaches, just‐in‐time (JIT) and theory of constraints (TOC), for designing and operating production lines have developed, each claiming to be the “correct” way. In addition there are still those who maintain that line balanced (whenever possible) is the optimal method. This study uses simulation to compare each of these approaches for designing and operating production lines under various levels of processing time variability, station downtime, and total system inventory. Not surprisingly, the JIT approach appears to work best when system variability is low. The TOC approach works best when system variability is high. This shows that lines designed using TOC principles perform significantly better than JIT lines when inventory is low, and JIT lines perform significantly better than TOC lines as inventory is added to the system. The traditionally balanced line did not perform best under any of the conditions used in this study.

Design, balancing, and sequencing are the key issues associated with assembly lines (ALs). The purpose of this paper is to identify AL design issues and to develop an integrated methodology for mixed‐model assembly line balancing (MMALB) and sequencing. Primarily, mixed‐model lines are utilized for high‐variety, low‐volume job shop or batch production. Variation of a generic product is important for the manufacturers as the demand is mostly customer driven in the present global market.

Different AL design norms, performance indexes, and AL workstation indexes have been identified in the initial stage of this work. As the paper progresses, it has focused towards an integrated approach for MMALB and sequencing addressed for small‐ and medium‐scale assembly plants. A small‐scale practical problem has been justified with this integrated methodology implemented by MATLAB.

ALs execution in the production floor require many important factors to be considered. Different line orientations, production approaches, line characteristics, performance and workstation indexes, problem definitions, balancing and product sequencing in accordance with the objective functions are needed to be taken into account by the line designer.

This paper has highlighted the important AL design characteristics and also provided an integrated approach for balancing mixed‐model assembly lines (MMALs) combined with sequencing heuristic. The findings of this paper can be helpful for the designers while designing an AL. The integrated approach for balancing and sequencing of MMALs can be used as a functional tool for assembly‐based contemporary industries.

The paper's aim is to assess the impact of product related features on the performances of assembly line manufacturing systems, also providing a specific Design for Manufacturing and Assembly rating index to assess the goodness of a product design solution with respect to assembly line performances.

A computer simulation‐based parametric analysis was carried out to assess the impact of four major product‐related parameters. 216 different assembly line balance problem instances were evaluated. Findings allowed to develop a DFMA rating index specific for assembly line manufacturing as well as design guidelines.

Assembly sequence degrees of freedom and the ratio of the average task duration to the maximum duration are the most influencing parameters. While the former should be maximized, only a moderate task duration variability was found beneficial. The influence of other factors resulted less marked and changing on a case‐specific basis.

Complex interactions between product design features and line performances prevent generalization. The performed numerical experimentation, although extensive, remains somewhat limited respect all possible practical situations. The proposed rating index should be utilized while maintaining an overall perspective about the mutual influence of all parameters. Some suggested guidelines imply a trade off with traditional DFMA guidelines.

Product designers are given useful insights, tools and guidelines to develop better producible products. With the proposed ranking index a designer can easily rate his choices when selecting assembly tasks and sequences, as well as rank alternative product designs solutions.

The paper presents an original discussion about the impact of product design choices on assembly line performances. The developed DFMA rating index and guidelines are new.

This paper, which will be published in two parts in consecutive issues of Circuit World, reproduces a chapter of the recently published book ‘Handbook of Printed Circuit Technology: New Processes, New Technologies’, edited by G. Herrmann and K. Egerer and published by Electrochemical Publications Ltd, Port Erin, Isle of Man.

The purpose of this study is to analyze the problem of optimal product line design in marketing channels.

This paper develops a game theoretic model, in which a firm markets a line of a limited number of products at different quality levels to serve a market composed of multiple consumer segments. The consumer segments are modeled as clusters of somewhat heterogeneous consumers as typically observed in the real world. These model characteristics allow us to consider a broader set of targeting strategies such as sub-segmentation and partial cannibalization which have not been considered previously. By considering both a vertically integrated channel and a decentralized channel, we investigate how channel structure influences optimal product line design. We analyze the model mathematically with supplemental numerical analyses.

Our analysis shows that “quality distortion” in product line design is not limited to the low-end product, as previously reported, but can happen to the high-end product. The direction of these quality distortions may be downward or upward, leading to either increased or decreased differentiation between the two products. Furthermore, channel decentralization makes it more likely for the firm to strategically choose upward partial cannibalization or sub-segmentation. Consequently, contrary to previous studies, we demonstrate that there exist conditions under which channel decentralization leads to higher product quality.

Our model reflects a more realistic market environment and a firm’s practical constraints than previous studies, which typically assume perfect homogeneity within each segment and/or the feasibility of offering an infinite number of products. This extension produces interesting new results and insights that provide more practical implications for a firm’s optimal product line design strategy.

Line balancing has been an important technique for manufacturing system design, because a completely balanced system can provide maximum resource utilization at the designed capacity. However, even if a system is completely balanced, it still has capacity waste when the entire product life cycle is considered, because real production is often significantly less than capacity. Avoiding this mismatch requires scalable systems such as reconfigurable manufacturing systems (RMSs) to meet changing product demand. Stage paralleling is suggested as an approach to scalability for RMSs. By comparing the economic feasibility of such manufacturing systems with completely balanced transfer line systems with respect to station cost, it is shown that line balancing is not necessarily desirable with this approach. The effect of station cost differences for unbalanced systems is also considered.