Balanced Line Research Articles

Alternative subgraphs assembly line balancing problem with resource selection and parallel stations

This article presents a novel alternative subgraphs assembly line balancing problem with resource selection and parallel stations. The model considers both the choice between different process alternatives and the selection of production resources for the various tasks. It also allows parallelization of stations in the balanced line, thereby improving the flexibility of the algorithm. The objective of optimization is to minimize the total cost of the planned line. A genetic algorithm is used for solving the model. To evaluate its functionality, the approach was applied to 486 well-known reference problems. In addition, the reference problems were expanded to create a new set of reference problems that serve as a benchmark for the algorithm’s new capabilities. The results show that the presented algorithm is feasible for solving the formulated assembly line balancing problem.

Balancing and Simulation Algorithm For Manual Assembly Line Operations.(Dept.M)

This work consists of a model which is based on a computerized algorithm and consists of two main parts namely balancing and simulation routines. This model was used to determine the buffer in-process units required between work stations along manual assembly lines. Since the task durations and deviations vary from assembly of one product to another and frum one task to another for the same product; this model was developed to handle different cases of wide and narrow Work variability according tu the type or assembly work. The model is capable of banding two different assembly line problem cases. Firstly in case of an assembly line production without balancing, the balancing routine is invited first to produce a balancing solution for the problem and then the simulation routine is Invited to determine the number of in-process units needed for each individual work station. Secondly in case of balanced assembly line production, the simulation routine is invited to simulate the work performance in each work station along the line and to determine the number of buffer in-process units needed for each individual work station. An assembly line problem consisting of fourteen tasks was used to test the balancing and simulation capability of the model. The problem was prepared to produce a perfect balancing solution of three work stations. The resultant balanced problem data was then used to Investigate the relationship between task variance, buffer in-process units between work stations and confidence level.

Solving the Type-2 Assembly Line Balancing with Setups Using Logic-Based Benders Decomposition

We solve the type-2 assembly line balancing problem in the presence of sequence-dependent setup times, denoted SUALBP-2. The problem consists of a set of tasks of a product, requiring to be processed in different assembly stations. Each task has a definite processing and setup times. The magnitude of setup times for each task is dependent on the processing sequence within each station. Processing and setup times of tasks assigned to each station constitute the station time. The goal is to minimize the cycle time (the maximum station time) by optimally (i) assigning tasks to assembly stations and (ii) sequencing these tasks within each station. To solve this challenging optimization problem, we first improve upon an existing mixed-integer programming (MIP) model by our proposed lower and upper bounds. These enhancements reduce the MIP model’s (solved CPLEX) average optimality gap from 41.61% to 20.77% on extra-large instances of the problem. To further overcome the intractability of the MIP model, we develop an exact logic-based Benders decomposition (LBBD) algorithm. The LBBD algorithm effectively incorporates a novel two-phase solution approach, the lower and upper bounds, various preprocessing techniques, relaxations, and valid inequalities. Using existing benchmarks in the literature, we demonstrate that our LBBD algorithm finds integer feasible solutions for 100% of all 788 instances (64% for the MIP), verifies optimality for 47% of instances (37% for the MIP), and achieves an average optimality gap of 5.04% (7.72% for the MIP obtained over 64% solved small instances). The LBBD algorithm also significantly reduces the computational time required to solve these benchmarks. Summary of Contribution: Assembly line balancing plays a crucial role in productivity enhancement in manufacturing and service companies. A balanced assembly line ensures higher throughput rate and fairer distribution of workload among assembly stations (workers). Assembly line balancing, in its simplest form, is one of the most challenging combinatorial optimization problems. Its complexity is further intensified when the sequence of executing tasks assigned to each station influences the magnitude of the setup performed between any two successive tasks. In view of such complexity, most assembly line balancing problems have been solved by randomized search techniques that do not provide any guarantee on the quality of solutions found. The mission of this paper is to understand whether there is any special structure within the existing mathematical models in the literature and, if so, exploit them toward developing computationally efficient exact techniques that can provide guarantee on the quality of solutions. Indeed, we demonstrate that such a special mathematical structure exists and we thus develop the first decomposition technique in form of a logic-based Benders decomposition (LBBD) to efficiently solve the type-2 sequence-dependent assembly line balancing problem. Specifically, we show that our LBBD significantly reduces cycle time and the time required for decision making. Our LBBD generalizes the scope of exact techniques for decision-making beyond the assembly line problems and is extendable to many other shop scheduling problems that arrange their stations (machines) serially and there are sequence-dependent setup times among their tasks.

SIZE REDUCTION OF KLOPFENSTEIN-BALUN TRANSFORMER FOR BALANCED ANTENNAS

A BALUN transformer converts impedance into another one and also converts an unbalanced line into a balanced line. A compact size broadband BALUN transformer is designed using Klopfenstein taper line transformer approach to transform 50Ω impedance into 100 Ω. The results of the conventional BALUN are compared with the proposed compact size BALUN. In order to reduce the length of the BALUN, a curved microstrip line is used. The proposed compact size BALUN is 56 %- 70 % smaller in size w.r.t the conventional BALUN but at the cost of 6% - 11% reduction in the overall band. The conventional BALUN has measured % bandwidth of 165 while the reduced size BALUN has 159. The measured results are in agreement with the simulated results.

Dual-Loop Arrays Fed by Coplanar Parallel Lines for Wideband Circular Polarization

Using the method of moments, we analyze three types of series-fed array antennas for circular polarization. First, we present a reference antenna's radiation characteristics with symmetrical dual loops fed by balanced parallel lines. Next, we modify the symmetrical dual loops into asymmetrical ones to enhance a circularly polarized (CP) wave bandwidth. It is found that the modified antenna has a bandwidth of 35% for a 3 dB gain-drop criterion, where the axial ratio is less than 3 dB. Finally, we use unbalanced parallel lines for feeding the asymmetrical dual loops to simplify the feed system. It is revealed that the antenna shows a CP wave bandwidth of 19%, which is twice as wide as that of the reference antenna.

A broadband and low cross‐polarization balanced dual‐polarized cross quasi‐yagi antenna

A broadband balanced fed dual-polarized cross quasi-Yagi antenna with a compact size, low cross-polarization, and good common-mode (CM) suppressions is provided. The proposed antenna consists mainly of two balanced quasi-Yagi antennas, which are vertical to each other. Balanced microstrip-slotline feeding line structures are utilized to excite the two quasi-Yagi antennas to achieve ±45° linear polarizations. A good end-fire radiation in a broad bandwidth is achieved by introducing the directors above the dipoles of the cross quasi-Yagi antenna. Meanwhile, a good wideband common-mode (CM) suppression and low cross-polarization levels are realized by the balanced microstrip-slotline feeding line structure. Besides, superior DM transmission and CM suppression are achieved intrinsically, thereby simplifying the design procedure significantly. Finally, the balanced dual-polarized antenna is fabricated to validate the feasibility of this design method. The measured dates show that the designed antenna characterizes broadband, high port isolation and CM suppression, low cross-polarization levels and stable gain radiation.

The operating behaviour of unbalanced, unpaced merging assembly lines

Unbalanced assembly line research has grown in importance because of its increasing applications in emerging economies, reverse logistics and remanufacturing. This paper examines the performance of numerous simulated patterns for reliable unbalanced manual merging assembly lines. The contribution of this study to the literature is that imbalance does not always negatively impact efficiency and that it can improve merging line performance when compared to a corresponding balanced merging line. The best performance was found to be a balanced line configuration and a monotone decreasing order for both parallel merging lines, with the former generally resulting in a lower throughput and the latter resulting in a lower average buffer level than that of a balanced line.

Estimation of transmission line parameters by using two least‐squares methods

This work proposes two new approaches based on the ordinary least-squares method and the total least-squares method to estimate the parameters of a balanced three-phase transmission line using voltage and current measurements from phasor measurement unit. First, a new model for the steady-state phasorial equations of a medium-length transmission line is proposed. Then, the noises acting upon each measurement on the ordinary least-squares setup are considered, and for the total least-squares setup, noise acting upon the observation matrix in order to account for model uncertainties and non-linearities is also considered. The methods are tested in simulation data of a real medium-size transmission line.s The main goal is to compare both methods and show their complexities. The results show good performances for both methods and, indeed, the total least-squares setup had better performance than other reported total least-squares estimators, which use a different phasorial set of equations and oversimplified noise modelling. It is concluded that for the ordinary least-squares, the solution is well known and its behavior is predictable. While for the total least-squares, the solution requires more sophisticated methods of matrix decomposition and its behavior is not as predictable. Therefore the implications of these new approaches, where new considerations about the modelling of the noises are made and where a new phasorial set of equations is used are significant, given that the many works in the literature make use of these common-place tools.

Analysis of balanced and unbalanced signal transmission lines and noise reduction technique for beam-current monitor in linear accelerators.

A signal transmission line and its characteristics were analyzed in detail for a beam-current monitor (CM) for long-pulsed electron beams. The monitor was based on a conventional current transformer, which comprised an induction coil wound around a ferrite core. The signal transmission and noise generation mechanism were analyzed by theoretical models based on balanced and unbalanced coaxial transmission circuits to effectively reduce noises superimposed on the beam-current signal waveform. The results of numerical analyses based on the theoretical models were in good agreement with those of an experiment for verification. It was found that the noise signals were generated by a high-power klystron operation and they were mode-transformed on the way to the transmission line. These results show that the locations of the grounded points in the transmission line were important. Based on a symmetrically configured three-line circuit theory, a new highly symmetrically configured coaxial transmission line is proposed to effectively suppress noises generated in CM. This report describes in detail the numerical and experimental analysis of a signal transmission line with coaxial cables for CM where the noise generation mechanism and its reduction technique are deeply involved.

Multi-fidelity surrogate-based optimization for decomposed buffer allocation problems

The buffer allocation problem (BAP) for flow lines has been extensively addressed in the literature. In the framework of iterative approaches, algorithms alternate an evaluative method and a generative method. Since an accurate estimation of system performance typically requires high computational effort, an efficient generative method reducing the number of iterations is desirable, for searching for the optimal buffer configuration in a reasonable time. In this work, an iterative optimization algorithm is proposed in which a highly accurate simulation is used as the evaluative method and a surrogate-based optimization is used as the generative method. The surrogate model of the system performance is built to select promising solutions so that an expensive simulation budget is avoided. The performance of the surrogate model is improved with the help of fast but rough estimators obtained with approximated analytical methods. The algorithm is embedded in a problem decomposition framework: several problem portions are solved hierarchically to reduce the solution space and to ease the search of the optimum solution. Further, the paper investigates a jumping strategy for practical application of the approach so that the algorithm response time is reduced. Numerical results are based on balanced and unbalanced flow lines composed of single-machine stations.

Alternative method using recursive convolution for electromagnetic transient analysis in balanced overhead transmission lines

This study proposes an alternative method to calculate the transient responses of multi-conductor overhead transmission lines based on ABCD representation, recursive convolutions and numerical method for rational approximation in the frequency-dependent curves. In the classical universal line model, the characteristic admittance matrix Y c ( ω ) and propagation matrix H ( ω ) are represented by rational functions. In H ( ω ) , previous and correct identification of the modal travelling times is required. However, these modal travelling times are estimated numerically, which do not offer good accuracy in some cases. This fact has a considerable effect on the rational representation of H ( ω ) itself and consequently on the transient responses. In the alternative method, a previous estimation of the modal travel times is unnecessary because when using the ABCD representation for each propagation mode, a direct relation exists between the currents and tensions of the receiving and sending ends. These relationships are fitted by smooth rational functions, and then, using recursive convolution methods, the authors obtain the explicit equations of the currents and voltages to calculate the transient responses. The results demonstrate that the alternative method is accurate when compared with the frequency-domain solution of the transmission line transformed to the time domain using the numeric Laplace transform and with the Bergeron method.

Energy transport and Anderson-like localization in non-Hermitian electrical transmission line

We investigate on the right and left-handed (RH/LH) balanced gain and loss non-Hermitian electrical transmission lines (ETL) modeled using an imaginary resistor. The hamiltonian of each system is successfully derived in the framework of the tight-binding theory. We discuss the underlying symmetries and calculate the breaking thresholds of the Parity time (PT) and Anti PT (APT) symmetry phase transitions. Moreover, the modes dynamic characterization reveal the existence of critical points beyond which operation requires thresholdless transition and the eigen modes are either real or complex. We also present a self-consistent theory to investigate on their scattering properties. In particular, we demonstrate that the Anderson-like localized modes mostly emerge in the broken phase where eigen modes are complex with the localization length proportional to the cell numbers. Importantly, the mode localization is most likely to occur in structures consisting of a large cells number for RH ETL while LH ETL will confined modes even for infinitesimal small cell numbers. These results unveil embryonic applications in cryptography, switching and system control.

PERBAIKAN LINTASAN PRODUKSI DENGAN PENERAPAN LARGE CANDIDATE RULE (LCR) DAN KILLBRIDGE AND WESTER PADA PROSES PRODUKSI DI PT EJ

PT. EJ is a company that manufactures stoves. Problems experienced by PT. EJ, the production line is not optimal. As a result this has resulted in waiting times at several existing work stations. This phenomenon occurs due to the inability of companies to control production trajectory times and improper allocation of machinery and human resources.
 The purpose of this study is to determine a balanced production line at PT. EJ to produce optimal production processes. The method used to support the purpose of this study is the Large Candidate Rule (LCR) and Killbridge & Wester methods. As a reference method with the highest recommended path efficiency results.
 The results of research conducted at PT. EJ is a condition that currently runs channel efficiency reaching 68.85%, delays in balance 31.15% and smoothness index 19.065 with the number of work stations 9. After the Killbridge & Wester method is applied, the channel efficiency value increases by 77.46 %, delays in balances decreased to 22.54% and the smoothness index increased at 10.76 with 8 work stations.

Balancing a multistage vehicle number plate production line using effective cycle time model

Shortest product cycle time is a key criterion for job sequencing and measuring competitiveness among entrepreneurial-based firms. Now, the long waiting time of job orders constitutes a deterministic production line problem in vehicle number plate production plants in Nigeria. Case studies were conducted on those plants, confidentially identified in this paper as A, B, C, and D. Delays caused by non-value-adding work processes are major culprits among other contributors to the long queues at these plants. The value stream mapping technique was applied to identify non-value adding activities before the production line was balanced using an effective cycle time model. The index cases to a balanced line, as shown in the results, are increases in process rate by 41 %, 59 %, 42 %, and 71 % for A, B, C, and D, respectively, and overall line efficiency. Next, the system capacities correspondingly increased with the elimination of wastages. These increments imply that bottleneck activities have been minimized, and we have a balanced production line. The devised solution procedure is reliable and recommended to other line manufacturing concerns that experience delays and bottleneck problems.

Visualizing the triple bottom line: A large‐scale automated visual content analysis of European corporations' website and social media images

AbstractWith the “visual turn” online, images have become increasingly important for companies to attract stakeholders to their online CSR communication. To investigate in how far businesses' visual sustainability language reflects a balanced triple bottom line, this study compared the most profitable European corporations' websites images (N = 21,841) and visual Twitter posts (N = 3,637) through automated content analysis using computer vision algorithms. The findings of this big data‐analysis reveal that European companies overemphasize the financial bottom line on both owned and shared media. The channel matters as firms are more likely to communicate people‐, planet‐, and profit‐related images via social media than their website. Corporations from environmentally sensitive industries tend to highlight the social dimension, though this is where they impact less, and do so more often through their website. Thus, this study confirms the criticism that the business case is dominant in CSR strategies also for visual communication.

Process Improvement at Automotive Assembly Line Using Line Balancing and Lean Manufacturing Approach

The aim of this study is to analyze the existing production line in the automotive industry and proposed a layout of improved production line in the manufacturing process and obtain the optimum rate of production time. Thus, line balancing method and Yamazumi Chart was utilized to analyze the current and proposed production line. The collection of the data of the existing production line was conducted at one of the automotive company in Malaysia. From the analysis of current production line, two improved layout were proposed and evaluated. The proposed layout was selected based on a balanced production line and ability to meet customer demand. A balanced production line will ensure smooth process and eliminate wastage during operation

Application of line balancing heuristics for achieving an effective layout: a case study.

This project is a case study conducted in a manufacturing company aiming at improving its productivity using line balancing techniques. Waste reduction, especially the time waste, is an important factor to shrink the manufacturing cost. The main purpose of this project is to suggest a better line balancing approach with an aim of reducing the idle time, work station number, and manpower requirement while improving the efficiency to meet the target production in the apparel manufacturing organization. For accomplishing the purpose, different line balancing methods named Largest Candidate Rule, Kilbridge & Wester method, and Ranked Positional Weight method carried out for analyzing the line efficiency, production rate, work station number, manpower requirement, and time utilization. Finally, an efficient and balanced line were proposed with respect to the auspicious outcome of the production area. Also, by using the line balancing techniques, a new sequence of work has been developed to arrange the work elements into the workstation. Some optimum layout has been proposed that has minimized the idle time and manpower requirement.

Compact Dual-Band Metamaterial-Based High-Efficiency Rectenna: An Application for Ambient Electromagnetic Energy Harvesting

A compact composite right/left-handed (CRLH)-based dualband rectenna is proposed for electromagnetic (EM) energy harvesting at the operating frequencies of Wi-Fi (2.5 GHz) and Worldwide Interoperability for Microwave Access (WiMAX) (3.6 GHz) bands. The rectenna consists of a dual-band antenna and dual-band rectifier. The antenna is realized in a microstrip topology using a balanced CRLH transmission line (TL) with an open termination. It measures 0.36 # 0.2 # 0.00049 mo (mo is the free-space guided wavelength) at 2.5 GHz and operates at 2.5 and 3.6 GHz, with an operating bandwidth of 4.75 and 3.3%, respectively, and a peak gain of 2.6 decibels relative to isotropic (dBi) at 2.5 GHz and 1.6 dBi at 3.6 GHz. The dual-band rectifier is designed using a novel CRLH-based microstrip topology composed of microstrip lines and lumped components. The overall rectifier volume is 0.3 # 0.2 # 0.0005 mo at 2.5 GHz. The measured radio-frequency (RF)?dc conversion efficiency is more than 59% at 2.5 GHz and 41% at 3.6 GHz, for an input power of 2 dB milliwatts (dBm) in both cases.

Lean Manufacturing Production Management Model focused on Worker Empowerment aimed at increasing Production Efficiency in the textile sector

For companies operating within the garment manufacturing industry, having frequent downtimes in their production flows is an extremely common issue. In this context, a balanced production line is required to prevent high waiting times due to limited productive capacity. A well-balanced assembly line allows products to be produced in an optimum time while using less resources, such as machines, materials, or labour, since the right number of products is produced with the exact amount of resources, thus generating savings in production costs. This paper seeks to foster optimum resource allocation through the line balancing tool. Finally, to define a work methodology, best practices were selected, and a procedures manual was developed focusing on Standardization. Both tools were implemented after implementing changes to the company culture by means of the Employee Empowerment tool. As a result of this implementation, workers acquired greater accountability and control over the resources, methods, and equipment of their work areas. After the proposed improvements had been deployed, the company reported an increase of over 20% in production line quality, performance, and efficiency.

Increasing flexibility and productivity in Industry 4.0 production networks with autonomous mobile robots and smart intralogistics

Manufacturing flexibility improves a firm’s ability to react in timely manner to customer demands and to increase production system productivity without incurring excessive costs and expending an excessive amount of resources. The emerging technologies in the Industry 4.0 era, such as cloud operations or industrial Artificial Intelligence, allow for new flexible production systems. We develop and test an analytical model for a throughput analysis and use it to reveal the conditions under which the autonomous mobile robots (AMR)-based flexible production networks are more advantageous as compared to the traditional production lines. Using a circular loop among workstations and inter-operational buffers, our model allows congestion to be avoided by utilizing multiple crosses and analyzing both the flow and the load/unload phases. The sensitivity analysis shows that the cost of the AMRs and the number of shifts are the key factors in improving flexibility and productivity. The outcomes of this research promote a deeper understanding of the role of AMRs in Industry 4.0-based production networks and can be utilized by production planners to determine optimal configurations and the associated performance impact of the AMR-based production networks in as compared to the traditionally balanced lines. This study supports the decision-makers in how the AMR in production systems in process industry can improve manufacturing performance in terms of productivity, flexibility, and costs.