Integrating product design and job scheduling on parallel machines

Bir üretim sisteminde temel amaç, müşteri taleplerinin zaman ve kalite boyutunda etkin bir şekilde karşılanmasıdır. Bu amacı gerçekleştirmek için üretimin büyük partiler halinde ve stok tutarak gerçekleştirilmesi daha mantıklı görünür. Ancak bu yaklaşım, üretim sistemindeki problemleri görünmez hale getirmekle beraber, uzun bekleme sürelerini içermesi nedeniyle üretim temin süresini, dolayısıyla katma değerli olmayan faaliyetlerin oranını arttırmaktadır. Bu durum neticesinde, firmaların hızlı yanıt kabiliyeti ve maliyet performansı olumsuz etkilenir. Paralel makinalarda sıraya bağımlı hazırlık sürelerine sahip işlerin çizelgelenmesini fazla üretim israfına yol açmayacak şekilde sağlayan bu çalışmada, öncelikle, işler arası sıraya bağımlı hazırlık süreleri, ürün tasarım özelliklerinden faydalanan bir matematiksel model ile belirlenmektedir. Böylece, sıraya bağımlı hazırlık süreleri bire-bir ölçüme gerek kalmadan belirlenebilmeleri ve hem güncel hem de güvenilir olmaları sağlanmıştır. Ayrıca, temin sürelerinde önemli bir yer tutan hazırlık sürelerinin düşürülmesi için sıraya bağımlı hazırlık süreleri, odaklanılması önem taşıyan unsurlar arasındadır. Bu bağlamda, sıraya bağımlı hazırlık süreleri toplamını azaltmaya yönelik olarak literatürde yer alan iki sıralama algoritması seçilmiş ve tasarım özelliklerine bağlı bir sıralama algoritması tasarlanmıştır. Sıralama safhasından sonra geliştirilen İş Yükü Bazlı İş Gönderme Sistematiği ile üretim sistem karakteristiğinin çekme sistemine yakınlaştırılması amaçlanmıştır. Geliştirilen metodolojinin performansını değerlendirmek üzere, gerçek bir elektrik donanımı üretim sisteminin kablo kesim-sıyırma-terminalleme sürecine odaklanılmıştır. Belirtilen süreçteki hazırlık işleri analiz edilmiş, ürün tasarım özellikleri belirlenmiştir. Gerçek üretim verileri ile sıralama yöntemlerinin karşılaştırılmasından sonra İş Yükü Bazlı İş Gönderme Sistematiği uygulanmıştır. Anahtar Kelimeler: Çizelgeleme, ürün tasarımı, iş yükü bazlı sipariş yönetimi, paralel makinalar.To gain the ability of designing, scheduling, and manufacturing the products, which customers exactly demand, in time provides competitive advantage to companies. The above mentioned ability is provided by implementing pull system between the costumer and supplier as well as manufacturing processes instead of push system. Such an approach is the reflection of being costumer oriented in production. In addition, setup time constitutes an important part of production lead time. Pull systems lead to significant achievement in terms of lead time when applied in the environment of short setup times which allows production in small batches. Scheduling problems are related to manufacturing resource planning (MRP) in the industrial context. Production managers must select an appropriate scheduling approach that will provide cost-efficient running of the production system. A scheduling approach that guarantees the cost efficient running of the factory is to minimize operational costs that include setup costs (times) which are very important in manufacturing industries. The setup time has often been considered to be negligible or as a part of the processing time. Otherwise, setup times are considered in two types, namely sequence independent and sequence dependent setup times. Sequence independent setup time depends only on the job to be processed while sequence dependent setup time depends on both the job to be processed and the immediately preceding job. Parallel machine problems, where each job can be processed on any of the machines but needs to be processed by only one machine, have a high level of importance in industrial scheduling because of the fact that many examples of the use of parallel machines can be found in the real world. The measurement of sequence dependent setup times becomes inefficient in terms of cost and time in production systems where increased product variey exists. Furthermore, in such systems, it is very difficult to update measured sequence dependent setup times. In this context, it is very efficient to utilize product design characteristics for the estimation of sequence dependent setup times. What is more, it is known in practice that controlling input rate has a great impact on the system performance. In manufacturing systems, this input regulation is performed by the Order Review/Release (ORR) function. Regarded as an effective capacity management tool, ORR manages the transition of production orders from the planning system to the shop floor. In ORR, production orders, that may be generated from a requirements planning system or directly originated from customer orders, are not immediately released to the shop floor without considering any information about the system or job characteristics. These jobs are often first collected in a pre-shop pool and then released to the system according to specific conditions. In this sense, ORR procedures can be considered as the link between production planning and production control as well as the link between manufacturing strategy and day by day management. The purpose of ORR is to improve system performance by controlling the flow of production orders to the system (i.e., the timing and conditions of order release decisions). These improvements can be achieved in terms of increased flexibility, decreased work in process (WIP), improved delivery performance, and decreased congestion and manufacturing lead times. When the relevant literature is reviewed, it is seen that there is not any scientific guiding work which not only considers product design in job scheduling, but also aims to prevent overproduction waste. In this thesis, an integrated methodology that uses product design specifications for job scheduling under the principle of Order Review/Release is developed. The proposed methodology is applied to a real wire harness industrial problem involving the cutting of cables with different colors, sizes and terminals on identical parallel machines with long sequence dependent setup times. The sequence dependent setup times are determined via a mathematical model without measurement. The scheduling objective is to minimize total sequence dependent setup time. Keywords: Scheduling, product design, order review/release, parallel machines

A New Extended MILP MRP Approach to Production Planning and Its Application in the Jewelry Industry

It is important to manage reverse material flows such as recycling, reusing, and remanufacturing in a production environment. This paper addresses a production planning problem which involves reusing of scrap and recycling of waste that occur in the various stages of the production process and remanufacturing/recycling of returns in a closed-loop supply chain environment. An extended material requirement planning (MRP) is proposed as a mixed integer linear programming (MILP) model which includes-beside forward-these reverse material flows. The proposed model is developed for the jewelry industry in Turkey, which uses gold as the primary resource of production. The aim is to manage these reverse material flows as a part of production planning to utilize resources. Considering the mostly unpredictable nature of reverse material flows, the proposed model is likewise transformed into a fuzzy model to provide a better review of production plan for the decision maker. The suggested model is examined through a case study to test the applicability and efficiency

The Utility of fNIRS Signals versus Self-Report for Classification of Fibromyalgia Syndrome

25th Signal Processing and Communications Applications Conference (SIU) -- MAY 15-18, 2017 -- Antalya, TURKEYEken, Aykut/0000-0002-7023-7930WOS: 000413813100133Fibromyalgia (FM) is a widespread painful disease that has a 2-8% prevalence. Its diagnosis is generally performed by American College of Rheumatology (ACR) criteria. However, these criteria are subjective and their reliability is controversial. In this study, painful stimulation and Transcutaneous Electrical Nerve Stimulation (TENS) were applied to both hands of healthy controls and FM patients and hemodynamic responses was measured by using Functional Near Infrared Spectroscopy (fNIRS). Features extracted from hemodynamic responses and self-report data were used with 4 different classifiers and 14 different parameters. In conclusion, classification performed by objective data collected from fNIRS signals (95%) gave higher accuracy than classification performed by subjective self-report data (83%). This study showed that painful stimulation and TENS application can be used to diagnose Fibromyalgia disease by using fNIRS.Turk Telekom, Arcelik A S, Aselsan, ARGENIT, HAVELSAN, NETAS, Adresgezgini, IEEE Turkey Sect, AVCR Informat Technologies, Cisco, i2i Syst, Integrated Syst & Syst Design, ENOVAS, FiGES Engn, MS Spektral, Istanbul Teknik UnivHigher Education Council (Yuksekogretim Kurumu - YOK)We would like to thank to Cemre Topcu for her help during data collection, This study was supported by Higher Education Council (Yuksekogretim Kurumu - YOK)

Differential Efficiency Of Transcutaneous Electrical Nerve Stimulation In Dominant Versus Nondominant Hands In Fibromyalgia: Placebo-Controlled Functional Near-Infrared Spectroscopy Study

Using functional near-infrared spectroscopy (fNIRS), modulation of hemodynamic responses by transcutaneous electrical nerve stimulation (TENS) during delivery of nociceptive stimulation was investigated in fibromyalgia (FM) patients and healthy controls for both hands. Two experiments were conducted: (1) median nerve stimulation with TENS and (2) painful stimulation using electronic von Frey filaments with TENS/placebo TENS. Mean Delta HbO(2) brain activity was compared across groups and conditions using factorial ANOVA. Dominant (right) hand stimulation indicated significant interactions between group and condition in both hemispheres. Post hoc results revealed that FM patients showed an increased activation in "pain + TENS" condition compared to the "pain + placebo TENS" condition while the brain activity patterns for these conditions in controls were reversed. Left-hand stimulation resulted in similar TENS effects (reduced activation for "pain + TENS" than " pain + placebo TENS") in both groups. TENS effects in FM patients might be manipulated by the stimulation side. While the nondominant hand was responsive to TENS treatment, the dominant hand was not. These results indicate that stimulation side might be an effective factor in FM treatment by using TENS. Future studies are needed to clarify the underlying mechanism for these findings. (c) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE).WoSScopu

Association of Fine Motor Loss and Allodynia in Fibromyalgia: An fNIRS Study

Recent studies showed that fine motor control dysfunction was observed in fibromyalgia (FM) syndrome as well as allodynia. However, brain signatures of this association still remain unclear. In this study, finger tapping task (FTT) and median nerve stimulation (MNS) were applied to both hands of 15 FM patients and healthy controls (HC) to understand this relationship. Hemodynamic activity was measured simultaneously using functional near-infrared spectroscopy (fNIRS). Experiments were analyzed separately by using 2x2 repeated measures ANOVA. Results for the FTT experiment revealed that HC showed higher activity than FM patients in bilateral superior parietal gyrus (SPG), left supramarginal gyrus (SMG) and right somatosensory cortex (SI). Furthermore, right-hand FTT resulted in higher activity than left-hand FTT in left SPG, left SI and right motor cortex (MI). In the MNS experiment, FM patients showed higher activity than HC in bilateral SPG, right SMG, right SI and right middle frontal gyrus (MFG). Negative correlation was observed in left SPG between FTT and MNS activities. Besides, MNS activity in left SPG was negatively correlated with left-hand pain threshold.This study revealed that left SPG might be an important indicator to associate fine motor loss and allodynia in FM