scholarly journals ANALISIS DAMPAK COMPONENT COMMONALITY TERHADAP SCHEDULE INSTABILITY PADA SISTEM RANTAI PASOK SEDERHANA

2018 ◽  
Vol 1 (1) ◽  
pp. 1-6
Author(s):  
Bilal Ahmadi ◽  
Dhany Surya Ratana
Keyword(s):  
Lead Time ◽  
Demand Uncertainty ◽  
Cost Structure ◽  
Supply Chain System ◽  
Common Component ◽  
Component Commonality ◽  
Operational Conditions ◽  
Uncertainty Product ◽  
Simulation Results ◽  
The Impact

This study analyzed the impact of component commonality to schedule instability. Analysis was implemented in the use of component commonality (use of same component in different product structures) in a simple supply chain system which is consist of one manufacturer and two suppliers. Different operational conditions were introduced such as: demand uncertainty, product cost structure, product lead time, product structure and inventory policy that company utilized. The simulation results suggested that common component could reduce schedule instability in both manufacturer and suppliers. Furthermore, the results also indicated that suppliers were the more affected entities due to uncertainty rather than manufacturer

scholarly journals ANALISIS DAMPAK COMPONENT COMMONALITY TERHADAP SCHEDULE INSTABILITY PADA SISTEM RANTAI PASOK SEDERHANA

2017 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
Bilal Ahmadi ◽  
Dhanny Surya Ratana
Keyword(s):  
Lead Time ◽  
Cost Structure ◽  
Common Component ◽  
Component Commonality ◽  
Structure Lead

<p>Penelitian ini menganalisis dampak penggunaan common component terhadap <br />ketidakpastian jadwal produksi. Analisis dilakukan pada penggunaan tingkat component <br />commonality (penggunaan komponen yang sama dalam struktur produk yang berbeda) tertentu <br />terhadap tingkat schedule instability pada sistem rantai pasok sederhana yang terdiri dari satu <br />pemanufaktur dan dua pemasok. Beragam kondisi operasional yang berbeda seperti: <br />ketidakpastian permintaan, cost structure, lead time, struktur produk serta kebijakan persediaan <br />yang diterapkan oleh perusahaan menjadi bagian yang diamati dalam studi ini. Hasil dari simulasi <br />menunjukkan penggunaan common component mampu mereduksi tingkat schedule instability, <br />baik pada pemanufaktur maupun pemasok. Selain itu juga tergambar dalam hasil tersebut bahwa <br />entitas pemasok mengalami instability yang lebih besar dibandingkan dengan pemanufaktur</p>

Analysis and Verification of Bullwhip Effect Based on System Dynamics

2013 ◽  
Vol 340 ◽  
pp. 312-319
Author(s):  
Fu Xin Yang ◽  
Bai Lan Zhang ◽  
Zhi Yuan Su
Keyword(s):  
Supply Chain ◽  
System Dynamics ◽  
Correlation Coefficient ◽  
Lead Time ◽  
Process Model ◽  
Autoregressive Process ◽  
Bullwhip Effect ◽  
Simulation Software ◽  
Simulation Results ◽  
The Impact

To study the bullwhip effect (BWE) in supply chain (SC), this paper built two system dynamics (SD) models strictly referring to the AR(1) (autoregressive process) model constructed by Frank Chen. Using Vensim simulation software, it analyzed the impact of the correlation coefficient of demand, lead time, smoothing time of demand and information to BWE, and then put forward some proposals on how to reduce BWE. By contrasting the simulation results of SD models with the AR(1) models', it verifies the validity of the AR(1) model of Frank Chen from a simulation perspective. It also shows SD model combined with AR(1) model can analyze BWE in SC reliably and powerfully.

scholarly journals Model Persediaan Pemasok-Pembeli Dengan Produk Cacat Dan Kecepatan Produksi Terkontrol.

2016 ◽  
Vol 15 (2) ◽  
pp. 103
Author(s):  
NELITA PUTRI SEJATI ◽  
WAKHID AHMAD JAUHARI ◽  
CUCUK NUR ROSYIDI
Keyword(s):  
Sensitivity Analysis ◽  
Production Rate ◽  
Lead Time ◽  
Demand Uncertainty ◽  
Lot Size ◽  
Defective Items ◽  
Total Cost ◽  
Joint Economic Lot Size ◽  
Demand Rate ◽  
The Impact

Penelitian ini mengembangkan model persediaan Joint Economic Lot Size (JELS) pada pemasok tunggal pembeli tunggal untuk jenis produk tunggal dengan mempertimbangkan produk cacat dan tingkat produksi terkontrol. Tingkat permintaan pada pembeli bersifat stokastik. Pengiriman dilakukan dari pemasok ke pembeli dalam ukuran lot pengiriman yang sama dan lead time pengiriman bersifat tetap. Produk cacat yang ditemukan oleh pembeli pada saat inspeksi disimpan secara sementara di gudang pembeli hingga pengiriman berikutnya tiba untuk selanjutnya produk cacat dikembalikan kepada pemasok. Fungsi tujuan dari model ini adalah meminimasi total biaya persediaan gabungan pemasok pembeli dengan variabel keputusan, yaitu frekuensi pengiriman, periode review, dan tingkat produksi. Analisis sensitivitas dilakukan untuk melihat pengaruh perubahan parameter-parameter tertentu terhadap model. Hasil yang didapatkan dari analisis sensitivitas menunjukkan bahwa total biaya persediaan gabungan sensitif terhadap perubahan nilai parameter persentase produk cacat, ketidakpastian permintaan, dan permintaan. In this paper, we consider a joint economic lot size (JELS) model consisting of single vendor single buyerwith single product. We intend to study the impact of defective items and controllable production rate onthe model. The demand in buyer side is assumed to be stochastic. The delivery of lot from vendor to buyer is conducted under equal size shipment and the lead time is assumed to be constant. The defective items founded by the inspector in buyer side are carried in buyer’s storage until the next shipment and will be returned to the vendor. The goal of the proposed model is to determine optimal delivery frequency, review period and production rate by minimizing the joint total cost. A sensitivity analysis is performed to show the impact of the changes of the decision variables on model’s behavior. The result from the sensitivity analysis shows that the joint total cost is sensitive to the changes of defect rate, demand uncertainty and demand rate. 

scholarly journals Why Do Companies Need Operational Flexibility to Reduce Waste at Source?

2021 ◽  
Vol 14 (1) ◽  
pp. 367
Author(s):  
Yara Kayyali Elalem ◽  
Isik Bicer ◽  
Ralf W. Seifert
Keyword(s):  
Lead Time ◽  
Demand Uncertainty ◽  
Evolutionary Dynamics ◽  
Environmental Benefits ◽  
Operational Flexibility ◽  
Lead Time Reduction ◽  
Multiple Sourcing ◽  
Quantity Flexibility ◽  
Time Reduction ◽  
The Impact

We analyze the environmental benefits of operational flexibility that emerge in the form of less product waste during the sourcing process by reducing overproduction. We consider three different options for operational flexibility: (1) lead-time reduction, (2) quantity-flexibility contracts, and (3) multiple sourcing. We use a multiplicative demand process to model the evolutionary dynamics of demand uncertainty. We then quantify the impact of key modeling parameters for each operational-flexibility strategy on the waste ratio, which is measured as the ratio of excess inventory when a certain operational-flexibility strategy is employed to the amount when an offshore supplier is utilized without any operational flexibility. We find that the lead-time reduction strategy has the maximum capability to reduce waste in the sourcing process of buyers, followed by the quantity-flexibility and multiple-sourcing strategies, respectively. Thus, our results indicate that operational-flexibility strategies that rely on the localization of production are key to reducing waste and improving environmental sustainability at source.

The ROLE OF CHINA-PAK ECONOMIC CORRIDOR (CPEC) IN LOGISTIC SYSTEM OF PAKISTAN’S AND CHINA’S

2019 ◽  
Vol 6 (1) ◽  
pp. 48-50
Author(s):  
Ikram Uddin
Keyword(s):  
Persian Gulf ◽  
Lead Time ◽  
Fiber Optic ◽  
Delivery Time ◽  
Fiber Optic Cable ◽  
Total Cost ◽  
Economic Complexity ◽  
Shipping Cost ◽  
The Impact

This study will explain the impact of China-Pak Economic Corridor (CPEC) on logistic system of China and Pakistan. This project is estimated investment of US $90 billion, CPEC project is consists of various sub-projects including energy, road, railway and fiber optic cable but major portion will be spent on energy. This project will start from Kashgar port of china to Gwadar port of Pakistan. Transportation is sub-function of logistic that consists of 44% total cost of logistic system and 20% total cost of production of manufacturing and mainly shipping cost and transit/delivery time are critical for logistic system. According to OEC (The Observing Economic Complexity) currently, china is importing crude oil which 13.4% from Persian Gulf. CPEC will china for lead time that will be reduced from 45 days to 10 days and distance from 2500km to 1300km. This new route will help to china for less transit/deliver time and shipping cost in terms of logistic of china. Pakistan’s transportation will also improve through road, railway and fiber optic cabal projects from Karachi-Peshawar it will have speed 160km per hour and with help of pipeline between Gwadar to Nawabshah gas will be transported from Iran. According to (www.cpec.inf.com) Pakistan logistic industry will grow by US $30.77 billion in the end of 2020.

scholarly journals Measuring Hydrometeors Using a Precipitation Microphysical Characteristics Sensor: Sampling Effect of Different Bin Sizes on Drop Size Distribution Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xichuan Liu ◽  
Taichang Gao ◽  
Yuntao Hu ◽  
Xiaojian Shu
Keyword(s):  
Drop Size ◽  
Rain Rate ◽  
Monte Carlo Model ◽  
Rain Gauge ◽  
Sampling Schemes ◽  
Distribution Parameters ◽  
Optimum Sampling ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

In order to improve the measurement of precipitation microphysical characteristics sensor (PMCS), the sampling process of raindrops by PMCS based on a particle-by-particle Monte-Carlo model was simulated to discuss the effect of different bin sizes on DSD measurement, and the optimum sampling bin sizes for PMCS were proposed based on the simulation results. The simulation results of five sampling schemes of bin sizes in four rain-rate categories show that the raw capture DSD has a significant fluctuation variation influenced by the capture probability, whereas the appropriate sampling bin size and width can reduce the impact of variation of raindrop number on DSD shape. A field measurement of a PMCS, an OTT PARSIVEL disdrometer, and a tipping bucket rain Gauge shows that the rain-rate and rainfall accumulations have good consistencies between PMCS, OTT, and Gauge; the DSD obtained by PMCS and OTT has a good agreement; the probability of N0, μ, and Λ shows that there is a good agreement between the Gamma parameters of PMCS and OTT; the fitted μ-Λ and Z-R relationship measured by PMCS is close to that measured by OTT, which validates the performance of PMCS on rain-rate, rainfall accumulation, and DSD related parameters.

scholarly journals A New Method to Determine the Impact of Individual Field Quantities on Cycle-to-Cycle Variations in a Spark-Ignited Gas Engine

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4136
Author(s):  
Clemens Gößnitzer ◽  
Shawn Givler
Keyword(s):  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Kinetic Energy ◽  
Negative Impact ◽  
Operating Conditions ◽  
Engine Operation ◽  
Gas Engine ◽  
Cycle Simulation ◽  
Simulation Results ◽  
The Impact

Cycle-to-cycle variations (CCV) in spark-ignited (SI) engines impose performance limitations and in the extreme limit can lead to very strong, potentially damaging cycles. Thus, CCV force sub-optimal engine operating conditions. A deeper understanding of CCV is key to enabling control strategies, improving engine design and reducing the negative impact of CCV on engine operation. This paper presents a new simulation strategy which allows investigation of the impact of individual physical quantities (e.g., flow field or turbulence quantities) on CCV separately. As a first step, multi-cycle unsteady Reynolds-averaged Navier–Stokes (uRANS) computational fluid dynamics (CFD) simulations of a spark-ignited natural gas engine are performed. For each cycle, simulation results just prior to each spark timing are taken. Next, simulation results from different cycles are combined: one quantity, e.g., the flow field, is extracted from a snapshot of one given cycle, and all other quantities are taken from a snapshot from a different cycle. Such a combination yields a new snapshot. With the combined snapshot, the simulation is continued until the end of combustion. The results obtained with combined snapshots show that the velocity field seems to have the highest impact on CCV. Turbulence intensity, quantified by the turbulent kinetic energy and turbulent kinetic energy dissipation rate, has a similar value for all snapshots. Thus, their impact on CCV is small compared to the flow field. This novel methodology is very flexible and allows investigation of the sources of CCV which have been difficult to investigate in the past.

scholarly journals Dynamic Adjustment Mechanism and Differential Game Model Construction of Mask Emergency Supply Chain Cooperation Based on COVID-19 Outbreak

2021 ◽  
Vol 13 (3) ◽  
pp. 1115
Author(s):  
Shufan Zhu ◽  
Kefan Xie ◽  
Ping Gui
Keyword(s):  
Supply Chain ◽  
Differential Game ◽  
Production Technology ◽  
Wholesale Price ◽  
Transfer Payment ◽  
Dynamic Adjustment ◽  
Supply Chain System ◽  
Government Subsidies ◽  
Technology Investment ◽  
The Impact

Incorporating the impact of the COVID-19 pandemic on the mask supply chain into our framework and taking mask output as a state variable, our study introduces the differential game to study the long-term dynamic cooperation of a two-echelon supply chain composed of the supplier and the manufacturer under government subsidies. The study elaborates that government subsidies can provide more effective incentives for supply chain members to cooperate in the production of masks compared with the situation of no government subsidies. A relatively low wholesale price can effectively increase the profits of supply chain members and the supply chain system. The joint contract of two-way cost-sharing contract and transfer payment contract can promote production technology investment efforts of the supply chain members, the optimum trajectory of mask production, and total profit to reach the best state as the centralized decision scenario within a certain range. Meanwhile, it is determined that the profits of supply chain members in the joint contract can be Pareto improvement compared with decentralized decision scenario. With the increase of production technology investment cost coefficients and output self-decay rate, mask outputs have shown a downward trend in the joint contract decision model. On the contrary, mask outputs would rise with growing sensitivity of mask output to production technology investment effort and increasing sensitivity of mask demand to mask output.

Sign in / Sign up

Export Citation Format

Share Document