ORDER PICKING SYSTEMS IN WAREHOUSE MANAGEMENT: A LITERATURE REVIEW

Sipariş toplama faaliyetleri, tedarik zinciri yönetiminde, hem üretim sistemleri açısından (montaj istasyonlarına alt  parçaların tedarik edilmesi), hem de dağıtım işlemleri açısından (müşteri taleplerinin karşılanması) kritik rol oynamaktadır.  Müşteri siparişlerindeki eğilimler, az sayıda ve yüksek miktarlarda siparişlerin çok sayıda ve düşük miktarlarda siparişlere  dönüştüğünü göstermektedir. Diğer yandan, talep edilen sipariş teslim süreleri ise her geçen gün kısalmaktadır. Bu  değişimler, işletmelerin piyasada rekabet edebilmeleri için etkin ve esnek bir sipariş toplama sistemi benimsemelerini  gerektirmektedir. Emek yoğun bir faaliyet olan sipariş toplama, tüm lojistik operasyonlarını ve müşteriye sağlanan hizmet  seviyesini büyük ölçüde etkilemektedir. Ayrıca, sipariş toplama süreci toplam depolama maliyetlerinin yarıdan fazlasını  oluşturmaktadır. Bu nedenle, sipariş toplama faaliyetlerinin en etkin şekilde gerçekleştirilmesi işletmeler için büyük önem  taşımaktadır. Belirli kısıtlar ve parametreler göz önünde bulundurularak sipariş toplama süresini veya mesafesini kısaltacak  şekilde sipariş toplama sürecinin planlanması son yıllarda birçok çalışmaya temel oluşturmaktadır. Bu çalışmada, depo  yönetiminde en uygun sipariş toplama sisteminin oluşturulmasında karar vericilere yol göstermek amacıyla, sipariş toplama  sürecinin tasarımı ve kontrolünde rol oynayan önemli faktörler ayrıntılı bir şekilde incelenmektedir. Bu kapsamda, depolarda  gerçekleşen ürün akış tipleri, sipariş toplama sistemlerinin sınıflandırılması, depolama alanlarına ürün atama kararları,  rotalama metotları, sipariş birleştirme ve bölgeleme politikaları ele alınmıştır. Order picking activities play a critical role in supply chain management in terms of both production systems (supplying components to assembly operations) and distribution operations (meeting customer demands). Trends in customer orders reveal that customer orders are transformed from few-and-large orders to many-and-small ones. On the other hand, lead times of customer orders get consistently shorter. Because of these changes, companies need to adopt an effective and flexible order picking system in order to remain competitive in the market. Order picking, as a labor intensive activity, deeply affects both overall logistic operations and service level provided to customers. Additionally, order picking process constitutes more than half of the total warehousing cost. For these reasons, it is crucial for companies to design and perform an effective order picking process. In recent years, planning the order picking systems that minimize the travel time or the travel distance, considering the specific constraints and parameters, has become the basis for many studies. In this study, critical factors that play role in design and control of order picking process is reviewed comprehensively to aid decision makers in constituting the optimal order picking system in warehouse management. In this context, product flow types in warehouses, classification of order picking systems, storage assignments decisions, routing methods, order batching, and zoning policies are investigated

A comparison of remifentanil and alfentanil infusions in abdominal surgery

Amaç: Bu çalısmada, abdominal cerrahi uygulanan hastalarda inhalasyon anestezisine eklenen remifentanil ve alfentanil infüzyonlarının etkinligi ve güvenirligi karsılastırıldı. Yöntem ve bulgular: ASA I-II, 22-65 yasları arasında 40 hasta rastgele iki gruba ayrılarak çalısmaya alındı. Indüksiyona, remifentanil grubunda (Grup R, n=20) 1 g/kg bolus ve 0.5 g/kg/dk remifentanil infüzyon dozu, alfentanil grubunda (Grup A, n=20) 25 g/kg bolus ve 1 g/kg/dk alfentanil infüzyon dozu ile baslandı ve her iki gruba bilinç kaybı saglanıncaya kadar 10 mg/10 sn hızda propofol verildi. Idame %0.5 end tidal izofluran, %66 N O/O ile saglandı. Entübasyondan 5 dakika sonra ilaç infüzyon dozları %50 azaltıldı. Remifentanil operasyon bitiminde, alfentanil ise 15 dakika önce sonlandırıldı. Cerrahiye otonomik ve somatik yanıt, bolus ve infüzyon artısları ile kontrol edildi. Derlenme; spontan solunum, yeterli solunum, sözel emre yanıt zamanları ve Aldrete skorlaması ile degerlendirildi. Cerrahiye hemodinamik yanıt, ilaç bolus ve infüzyon artısları Grup A'da, hipotansiyon ve bradikardi, Grup R'de daha fazla bulundu. Yeterli solunum, ekstübasyon ve sözel emre yanıt verme zamanları Grup R'de daha kısa, Aldrete skorları ise benzer bulundu. Sonuç: Bu çalısmada kullanılan infüzyon dozlarında remifentanil, intraoperatif hemodinamik yanıtı daha iyi kontrol ederken, hızlı derlenme özelligi ile de alfentanilden daha etkin ve güvenli bulundu.Objective: We studied the efficacy and safety of remifentanil and alfentanil infusions in combination with inhalational anesthesia during abdominal surgery. Material and methods: Forty patients, ASA I-II, aged between 22-65 years were randomly allocated into two groups. Anesthesia was induced with remifentanil 1 mg/kg bolus, followed by 0.5 mg/kg/min infusion in the remifentanil group (Group R, n=20), alfentanil 25 mg/kg bolus and 1 mg/kg/min infusion in the alfentanil group (Group A, n=20) and propofol was given at a rate of 10 mg/10 sec until loss of consciousness. Lungs were ventilated with 0.5% end-tidal isoflurane and 66% N2O/O2. Infusion rates were reduced by 50% 5 minutes after intubation. Remifentanil was discontinued at the end of operation and alfentanil 15 minutes before. Autonomic and somatic responses to surgery were controlled with bolus and infusion rate increases. Recovery was assessed with the time for spontaneous and adequate respiration, response to verbal command and Aldrete scores. Results: Hemodynamic response to surgery, drug boluses and increases in infusion rates were found to be higher in Group A, while incidences of hypotension and bradycardia were higher in Group R. In Group R, adequate respiration, extubation and response to verbal command were shorter and Aldrete scores were similar. Conclusion: Remifentanil, when administered at the same doses with this study, controlled intraoperative hemodynamic response better in comparison with alfentanil and was found to be more effective and safe because of its rapid recovery properties

Global survey of the roles, satisfaction, and barriers of home healthcare nurses on the provision of palliative care

Background: the World Health Assembly urges members to build palliative care (PC) capacity as an ethical imperative. Nurses provide PC services in a variety of settings, including the home and may be the only health care professional able to access some disparate populations. Identifying current nursing services, resources, and satisfaction and barriers to nursing practice are essential to build global PC capacity. Objective: to globally examine home health care nurses' practice, satisfaction, and barriers, regarding existing palliative home care provision. Design: needs assessment survey. Setting/Subjects: five hundred thirty-two home health care nurses in 29 countries. Measurements: a needs assessment, developed through literature review and cognitive interviewing. Results: nurses from developing countries performed more duties compared with those from high-income countries, suggesting a lack of resources in developing countries. Significant barriers to providing home care exist: personnel shortages, lack of funding and policies, poor access to end-of-life or hospice services, and decreased community awareness of services provided. Respondents identified lack of time, funding, and coverages as primary educational barriers. In-person local meetings and online courses were suggested as strategies to promote learning. Conclusions: it is imperative that home health care nurses have adequate resources to build PC capacity globally, which is so desperately needed. Nurses must be up to date on current evidence and practice within an evidence-based PC framework. Health care policy to increase necessary resources and the development of a multifaceted intervention to facilitate education about PC is indicated to build global capacity

HOW CAN RISKS BE MANAGED IN LOGISTICS NETWORKS

Risk Management is a subject of growing interest both in academic research and in business communities. Nowadays the industrial environment is highly dynamic and sometimes unstable. Because of the structural complexity and volatility in logistics networks, there is an increasing need for a decision support system that is integrated with risk assessment and management procedures. In this study, we aim to investigate the fundamental steps of risk analysis and management, then present a conceptual framework of a design methodology for a well-suited control mechanism and systematic decision-making process of logistics networks under the influence of disruptive factors

An integrated modeling approach for shop-floor scheduling and control problem of flexible manufacturing systems

Increasing automation and complexity of today's production systems affect the constraints of real-world shop-floor control and scheduling problems. To deal with these constraints, either the existing modeling and analysis techniques were improved or new scheduling approaches were developed. This study attempts to propose an object-oriented approach for modeling and analysis of shop-floor scheduling problem of flexible manufacturing systems (FMSs) using high-level Petri Nets (PNs). The graphical nature and mathematical foundation has made PN-based methods appealing in real-time scheduling and control of FMSs. In the proposed approach, we firstly construct an object-modeling diagram of an FMS and develop a heuristic rule-base to solve the resource contention problem then formulate the dynamic behavior of the system by high-level PNs. The modeling methodology is illustrated by an FMS, and the proposed rule-based system is compared with several dispatching rules with respect to part flow time and tardiness-related performance measures

A High-level Petri Net Based Modeling Approach for Risk Management in Supply Chain Networks

8 pagesInternational audienceThe aim of this study is to show, how a Supply Chain (SC) management problem can be formulated in a timed Petri nets framework, and how this model can easily be extended to cover risk management applications. In this paper, the risk management procedures are integrated into design, planning, and performance evaluation process of supply chain networks through Petri net based simulation. The developed methodology provides an environment for defining uncertainties in the system and mitigation of risk factors. We show that, the PN framework provides an easy integration of risk management modules in the supply chain mode

Risk assessment and management for supply chain networks: A case study

International audienceThe aim of this study is to show how a timed Petri nets framework can be used to model and analyze a supply chain (SC) network which is subject to various risks. The method is illustrated by an industrial case study. We first investigate the disruption factors of the SC network by a failure mode, effects and criticality analysis (FMECA) technique. We then integrate the risk management procedures into design, planning, and performance evaluation process of supply chain networks through Petri net (PN) based simulation. The developed PN model provides an efficient environment for defining uncertainties in the system and evaluating the added value of the risk mitigation actions. The findings of the case study shows that the system performance can be improved using risk management actions and the overall system costs can be reduced by mitigation scenarios