Optimization Research of Construction Inventory Management on Site Based on Inventory Theory

2012 ◽  
Vol 209-211 ◽  
pp. 1321-1325
Author(s):  
Ai Juan Zou
Keyword(s):  
Inventory Management ◽  
Operations Research ◽  
Economic Benefit ◽  
Lead Time ◽  
Order Quantity ◽  
Inventory Theory ◽  
Procurement Management ◽  
Total Cost ◽  
Total Inventory ◽  
Project Procurement

Inventory management is to improve economic benefit of project procurement management by means of dominating order cycle and order quantity to minimize the stocks and total cost under the circumstance of normal construction.Firstly,inventory management involves material order,and contractors need to calculate parameters such as order cycle,order fee,order quantity,stocks fee,order lead time and safe stocks in order to make the total inventory fee minimized during construction.This article applies one branch of operations research--"inventory" to optimize the inventory management.

scholarly journals PERENCANAAN DAN PENGENDALIAN PERSEDIAAN BAHAN BAKU PAIL CAT MENGGUNAKAN METODE MATERIAL REQUIRMENT PLANNING (MRP) PADA PT. XYZ

JUMINTEN ◽  
2020 ◽  
Vol 1 (4) ◽  
pp. 163-172
Author(s):  
Vify Elviana ◽  
Akmal Suryadi
Keyword(s):  
Inventory Management ◽  
Consumer Demand ◽  
Raw Materials ◽  
Raw Material ◽  
Economic Order Quantity ◽  
Economic Order ◽  
Order Quantity ◽  
Material Requirements Planning ◽  
Total Cost ◽  
Material Requirements

Persediaan merupakan aset perusahaan yang memiliki peran penting dalam operasi bisnis, sehingga perusahaan penting untuk melakukan manajemen persediaan yang baik, artinya perusahaan harus mampu mengantisipasi kendala maupun tantangan yang ada dalam pengelolahan persediaan untuk meminimalisasi total biaya yang harus dikeluarkan oleh perusahaan. Permasalahan yang timbul pada persediaan bahan baku di PT XYZ adalah perusahaan melakukan perencanaan dan pengendalian bahan baku hanya berdasarkan pada pengalaman-pengalaman sebelumnya dan tidak berdasarkan pada metode yang sudah baku. Oleh karena itu pembelian bahan baku tidak sesuai dengan permintaan konsumen. Hal tersebut sering menyebabkan terjadinya kelebihan maupun kekurangan stok bahan baku. Kesalahan dalam penentuan besarnya investasi dalam persediaan akan mengurangi keuntungan perusahaan. Adanya persediaan bahan baku yang terlalu besar, akan menambah beban biaya pemeliharaan dan penyimpanan dalam gudang, serta kemungkinan terjadinya penurunan kualitas bahan baku yang dapat menyebabkan berkurangnya keuntungan perusahaan. Namun jika persediaan bahan baku terlalu sedikit maka akan berakibat pada terhambatnya proses produksi, sehingga tidak terpenuhinya permintaan konsumen. Hasil penelitian ini dapat menyimpulkan bahwa perencanaan kebutuhan bahan baku dengan metode perusahaan didapatkan total cost sebesar Rp 1.796.762.429,-, sedangkan metode Material Requirements Planning (MRP) didapatkan total cost sebesar Rp 1.576.011.801,-. Maka dapat disimpulkan telah terjadi penurunan total cost seluruh bahan baku sebesar 12,28%. Hal ini membuktikan bahwa metode Material Requirements Planning (MRP) lebih efisien daripada metode PT. XYZ. Oleh karena itu untuk mendapatkan total cost yang minimum, metode Material Requirements Planning (MRP) diterapkan pada periode Februari-Juni 2020 sehingga didapatkan total cost sebesar Rp 1.576.011.801,-. Kata Kunci:         Material Requirements Planning (MRP), PT XYZ, Pail Cat, Economic Order Quantity (EOQ), Period Order Quantity (POQ), Lot For Lot (LFL). ABSTRACT                     Inventory is a company asset that has an important role in business operations, so the company is important to conduct good inventory management, meaning that the company must be able to anticipate obstacles and challenges that exist in managing inventory to minimize the total cost to be incurred by the company.The problem that arises in the supply of raw materials in PT XYZ is that the company plans and controls raw materials based only on previous experiences and not based on established methods. Therefore, the purchase of raw materials is not in accordance with consumer demand. This often leads to excess or shortage of raw material stock. Mistakes in determining the amount of investment in inventories will reduce company profits. The availability of raw materials that are too large, will add to the burden of maintenance and storage costs in the warehouse, as well as the possibility of a decline in the quality of raw materials that can lead to reduced company profits. However, if the supply of raw materials is too little, it will result in obstruction of the production process, so that consumer demand is not fulfilled. The results of this study can conclude that the planning of raw material needs by the company method obtained a total cost of Rp 1,796,762,429, - while the Material Requirements Planning (MRP) method obtained a total cost of Rp 1,576,011,801, -. Then it can be concluded that there has been a decrease in the total cost of all raw materials by 12.28%. This proves that the Material Requirements Planning (MRP) method is more efficient than the PT. XYZ. Therefore, to get the minimum total cost, the Material Requirements Planning (MRP) method was applied in the February-June 2020 period so that a total cost of Rp 1,576,011,801 was obtained.   KeyWords: Material Requirements Planning (MRP), PT XYZ, Pail Cat, Economic Order Quantity (EOQ), Period Order Quantity (POQ), Lot for Lot (LFL).

scholarly journals Analisis Pengendalian Persediaan Bahan Baku dengan Menerapkan Metode EOQ (Economic Order Quantity) pada PT. Jatisari Furniture Work

2021 ◽  
Vol 5 (1) ◽  
pp. 215
Author(s):  
Arga Sutrisna ◽  
Rizki Ginanjar ◽  
Suci Putri Lestari
Keyword(s):  
Production Costs ◽  
Raw Material ◽  
Economic Order Quantity ◽  
Economic Order ◽  
Analysis Tool ◽  
Order Quantity ◽  
Inventory Cost ◽  
Total Cost ◽  
Inventory Costs ◽  
Total Inventory

This research objectives aims to determine and analyze raw material inventory control, the ideal raw material inventory that the company must provide and the efficiency of production costs carried out by Jatisri Furniture Work in Tasikmalaya for the period 2018.11 – 2020.02. The data collection method in this study is by direct observation at Jatisari Furniture Work in Tasikmalaya. Using techniques such us interviews, observation, and documentation. These observations were made in production reports for the years 2018 – 2020. The analysis tool was carried out using the Economic Order Quantity (EOQ) method such us safety stock, reorder point, and total inventory cost. The result of the Economic Order Quantity (EOQ) analysis show that the total cost of raw the material inventory that must be incurred by the company is greater than the total cost of inventories calculated according to the EOQ method. Companies should follow the calculations from the EOQ method so that they can save on raw material inventory costs, so that production costs are more efficient.

scholarly journals Inventory model for deteriorating items with negative exponential demand, probabilistic deterioration and fuzzy lead time under partial back logging

2020 ◽  
Vol 30 (3) ◽  
Author(s):  
Nabendu Sen ◽  
Sumit Saha
Keyword(s):  
Inventory Management ◽  
Lead Time ◽  
Probability Distributions ◽  
Optimal Strategies ◽  
Inventory Model ◽  
Deteriorating Items ◽  
Optimal Time ◽  
Inventory Cost ◽  
Total Inventory ◽  
Negative Exponential

The effect of lead time plays an important role in inventory management. It is also important to study the optimal strategies when the lead time is not precisely known to the decision makers. The aim of this paper is to examine the inventory model for deteriorating items with fuzzy lead time, negative exponential demand, and partially backlogged shortages. This model is unique in its nature due to probabilistic deterioration along with fuzzy lead time. The fuzzy lead time is assumed to be triangular, parabolic, trapezoidal numbers and the graded mean integration representation method is used for the defuzzification purpose. Moreover, three different types of probability distributions, namely uniform, triangular and Beta are used for rate of deterioration to find optimal time and associated total inventory cost. The developed model is validated numerically and values of optimal time and total inventory cost are given in tabular form, corresponding to different probability distribution and fuzzy lead-time. The sensitivity analysis is performed on variation of key parameters to observe its effect on the developed model. Graphical representations are also given in support of derived optimal inventory cost vs. time.

scholarly journals SUPPLY LEAD TIME UNCERTAINTY IN A SUSTAINABLE ORDER QUANTITY INVENTORY MODEL

2013 ◽  
Vol 4 (4) ◽  
pp. 15-27 ◽  
Author(s):  
Salvatore Digiesi ◽  
Giorgio Mossa ◽  
Giovanni Mummolo
Keyword(s):  
Inventory Management ◽  
Lead Time ◽  
Expected Value ◽  
Air Pollutant ◽  
Pollutant Emission ◽  
Optimal Order ◽  
Inventory Level ◽  
Order Quantity ◽  
Industrial Case Study ◽  
Safety Stock

Abstract Transport plays a key role in inventory management since it affects logistic costs as well as environmental performance of the supply chain. Expected value and variability of supply lead time depend on the transportation means adopted, and influence the optimal values of order quantity, reorder level, and safety stock to be adopted. Fast transportation means allow reducing expected value of the lead time; they are characterized by the highest costs of externalities (i.e. air pollutant emission, noise, congestion, accidents). On the contrary, slow transportation means require high inventory level due to large order quantity; in this case costs of externalities tend to decrease. The Sustainable Order Quantity (SOQ) [1] allows identifying optimal order quantity, reorder level, safety stock as well as transportation means which minimize the sum of the logistic and environmental costs in case of stochastic variability of product demand. In this paper, the authors propose a new SOQ analytical model considering stochastic variability of supply lead time (LT). A solution procedure is suggested for solving the proposed model. The approach is applied to a real industrial case study in order to evaluate the benefits of applying it if compared with the traditional one.

scholarly journals KUANTITAS PEMESANAN EKONOMIS BAHAN BAKU TEPUNG PADA USAHA ROTI SURYA BAKERY KOTA BANGKULU

2019 ◽  
Vol 12 (1) ◽  
pp. 124-140
Author(s):  
Virda Palupi ◽  
Trisna Murni ◽  
Syamsul Bachri ◽  
Sri Warsono
Keyword(s):  
Wheat Flour ◽  
Lead Time ◽  
Quantitative Method ◽  
Secondary Data ◽  
Raw Material ◽  
Economic Order Quantity ◽  
Economic Order ◽  
Order Quantity ◽  
Total Cost ◽  
Descriptive Qualitative

This study aimed to analyze the Economic order quantity level of raw material wheat flour for Surya Bakery and the quantity level of Re-order Point. The design of study was descriptive qualitative. The study used secondary data in order to gain the information about purchasing of raw material of flour. The data analyzed by quantitative method which used Economic Order Quantity (EOQ) method and Re-order Point. The result shows that EOQ in Usaha Roti Surya Bakery is 4.266 kg with frequency of ordering raw material is 22 times. Wher eas re-order point of the raw material when inventory reach 1.068 kg with lead time are 4 days. Before using EOQ method, the frequency of ordering raw material of flour is 36 times per year. After using EOQ method, it is found the frequency of ordering raw material of flour is 22 times per year. So that, after using EOQ method, the result of ordering cost was Rp. 2.668.00,- carrying cost was Rp. 2.615.000,-, and total cost of raw material was Rp. 5.283.000,-. Therefore, the Surya-Bakery could save money for Rp 533.000 per year.

scholarly journals Manajemen Persediaan Tepung Terigu dengan Metode Economic Order Quantity (EOQ) pada Perusahaan Roti Nikki Echo Payakumbuh

2018 ◽  
Vol 1 (1) ◽  
pp. 21-27
Author(s):  
Desi Rahma Yani ◽  
Mega Amelia Putri ◽  
John Nefri
Keyword(s):  
Inventory Management ◽  
Production Cost ◽  
Raw Material ◽  
Economic Order Quantity ◽  
Economic Order ◽  
Order Quantity ◽  
Inventory Cost ◽  
Company Policy ◽  
Total Inventory ◽  
A Company

Inventory management has an important role in a company because inventory management can decrease production cost. Economic order quantity using to minimize the production cost. Inventory management of flour in bread company Nikki Echo not been seen clearly prove by  so many booking amount. It can giving addition of cost. The purpose of this research is (1) Analyzing optimal flour stock by using EOQ method in bread company Nikki Echo, (2) Analyzing reorder point raw material inventory by using EOQ method in bread company Nikki Echo, (3) Analyzing total raw material inventory cost by using EOQ method in bread company Nikki Echo. This research be held from February 20 until April 19 2018 in bread company Nikki Echo, Tanjung Pauh, Payakumbuh city, West Sumatera province. Flour stock by using EOQ method as much 17.394 kg it means the amount greater than company policy. That amount increase 79,6% from the amount set by company. Frequency of booking less than company policy that is 7 times booking. Amount of reorder by using EOQ method is 10.251 kg with the inventory lead time for 3 days. Total inventory cost by using EOQ method as many Rp 11.445.513. This value small than total inventory cost issued by company policy. Decreasing cost amount 98% from company policy. That cause by ordering amount reduced 33 times or same with 82,5% from the amount before

scholarly journals Decreasing Total Inventory Cost by Controlling Inventory in Motorcycle Dealer

2020 ◽  
Vol 22 (2) ◽  
pp. 41-49
Author(s):  
David ◽  
Engmir ◽  
Irwan Budiman ◽  
Jusra Tampubolon
Keyword(s):  
Inventory Management ◽  
Demand Forecasting ◽  
Spare Parts ◽  
Order Quantity ◽  
Inventory Cost ◽  
Safety Stock ◽  
Safety Stocks ◽  
Forecasting Method ◽  
Total Inventory ◽  
Abc Analysis

This research was conducted at one of the motorcycle dealers in Indonesia. Besides selling motorcycles, this dealer also provides services to repair motorcycles and sells genuine motorcycle parts. Inventory management which the company carried out is still not good enough because there are still demand for spare parts from consumers that cannot be fulfilled by the company. The purpose of this study is to draw up a plan to control spare parts by paying attention to the spare parts that need to be considered, estimating the exact number of spare parts demand, knowing the smallest total inventory cost, knowing the amount of safety stock needed, and knowing when to reorder. In preparing the spare parts control, the methods used are ABC analysis, demand forecasting method, and EOQ method. The results of this study are plans to control the inventory of Tire, Rr. such as the forecasting sales of Tire, Rr. as many as 17338, economic order quantity of Tire Rr are 2158 units, the number of safety stocks of Tire, Rr. needed in 2020 are 1738 units, and the reorder point in 2020 is 8 times with the total inventory cost for Tire, Rr. in 2020 is Rp. 30,009,005.

scholarly journals ANALISIS KINERJA MANAJEMEN PERSEDIAAN PRODUK UD. SINAR JAYA KARANGASEM

2021 ◽  
Vol 10 (3) ◽  
pp. 270
Author(s):  
I Putu Adi Sanjaya ◽  
Ni Ketut Purnawati
Keyword(s):  
Inventory Management ◽  
Descriptive Analysis ◽  
Safety Stock ◽  
Total Cost ◽  
Inventory Costs ◽  
Actual Application ◽  
Total Inventory ◽  
Operational Activities ◽  
Abc Analysis ◽  
Product Inventory

Inventory plays an important role in the company's operational activities, it is necessary to do inventory management in order to minimize losses caused by the large inventory costs. This research is conducted at UD. Sinar Jaya, aims to determine the performance of product inventory management and whether it’s efficient or not. Research data are obtained through interviews and observations. Descriptive analysis technique is used, which describes systematically several stages starting with ABC analysis, EOQ calculation, safety stock calculation, re-order point calculation, maximum inventory calculation, inventory turnover calculation, and comparing the total inventory cost between the method applied by the company with the EOQ method. Results show that product inventory management performance is not efficient. This is indicated by the total cost of inventory incurred using the company method in 2019 amounting to IDR 43,058,137. The product inventory management system that should be carried out is to classify products with ABC analysis, then determine EOQ of 1,208 units, determine safety stock of 518 units, and determine the re-order point of 1,099 units for each classification at unit A, so that the total cost of inventory incurred is only IDR 32,716,517 or 24.02 % lower than the actual application of company methods. Keywords: ABC analysis, EOQ, inventory costs

scholarly journals Pengembangan Model Vendor Managed Inventory dengan Banyak Retailer yang Mempertimbangkan Ketidakpastian Lead Times

2018 ◽  
Vol 7 (1) ◽  
pp. 41
Author(s):  
Carles Sitompul ◽  
Paulina Ariningsih ◽  
Ida Bagus Deva Narswara Santosa
Keyword(s):  
Inventory Management ◽  
Lead Time ◽  
Mathematical Formulation ◽  
Lead Times ◽  
Approximation Model ◽  
Vendor Managed Inventory ◽  
Inventory Cost ◽  
Inventory Management System ◽  
Total Inventory ◽  
The Cost

<p><em>An inventory management system in supply chains called Vendor Managed Inventory (VMI) is very promising due to the cost efficiency resulted from implementing such system. This research aims to develop a vendor managed inventory for multiple retailers. The model also takes into account lead time uncertainties from vendor to its retailers. A mathematical formulation for VMI with multiple retailers is first developed using deterministic lead times.  Subsequently, lead times uncertainties are then taken into account where modes lead times are broken into two components: modes and delays, each with their respective probabilities. In turn, an approximation model is used to solve the problem because the complexity aroused from the model is difficult to solve using analytical methods. It is shown that the proposed approximation method is able to solve VMI problem with multiple retailers and uncertain lead times.  Furthermore, the total inventory cost is significantly reduced when compared to the usual economic order quantity method because stockouts are less frequent. </em></p>

scholarly journals Optimizing Production Process through Production Planning and Inventory Management in Motorcycle Chains Manufacturer

2018 ◽  
Vol 9 (2) ◽  
pp. 43
Author(s):  
Shelvy Kurniawan ◽  
Steven Sanjaya Raphaeli
Keyword(s):  
Production Planning ◽  
Inventory Management ◽  
Decomposition Method ◽  
Moving Average ◽  
Order Quantity ◽  
Production Schedule ◽  
Multiplicative Decomposition ◽  
Additive Decomposition ◽  
Transportation Model ◽  
Total Cost

Based on the data, there were still shortages of production from year to year and demand wereunstable in motorcycle chains manufacturer in Indonesia. To overcome these problems, the purpose of this research was to make production planning and inventory control consisting of forecasting, aggregate planning, Master Production Schedule (MPS), and Material RequirementsPlanning (MRP). Forecasting used the additive decomposition method (average of all data), multiplicative decomposition (centered on moving average), and winter method (additive and multiplicative). Aggregate planning used chase strategy, level strategy, and transportation model. Moreover, MRP used lot for lot, Economic Order Quantity (EOQ), and Periodic Order Quantity (POQ) methods. The test shows several results. First, the best forecasting is additive decomposition (average of all data) with MAD value of 3.033,57, MSE with 13.590.490,and MAPE with 10,083%. Second, the best aggregate planning is transportation model with the total cost of Rp7.708.398.390,00. Last, the best MRP method is the lot for lot with total cost Rp7.162.567.653,00.

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