Khawarita Siregar’s research while affiliated with University of North Sumatra and other places

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Publications (29)


Figure 1. Injection Moulding Machine
Figure 2. Phases and applications of an LCA (based on ISO 14040, 1997)
Global Environmental Impact of Plastic Flower Pot Production and Other Materials
Life Cycle Analysis Study of Plastic Flower Pot Products
  • Article
  • Full-text available

July 2024

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308 Reads

Jurnal Sistem Teknik Industri

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Khawarita Siregar

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SS Sarjana

Some flower pots are made of plastic materials. Plastic waste is a global environmental issue with varying quantities and types in different countries. One source of plastic pollution is low-durability plastic pots, commonly used for seeding in agriculture, horticulture, and forestry. Waste from these plastic pots is difficult to decompose by soil microbes, thus posing an environmental contamination risk. Life Cycle Analysis (LCA), also known as life cycle assessment, is a method to measure the environmental impacts of products, such as biofuels. In LCA, researchers prepare an inventory of the resources used (e.g., fossil fuels and raw materials) and substances produced (e.g., greenhouse gases, solid waste, and other pollutants) throughout the full life cycle of production, transportation, and use of the product in question. From this inventory, researchers conduct impact assessments that estimate the final effects on human health, ecosystem function, and depletion of natural resources. This study aims to assess the life cycle analysis of plastic flower pot products from their initial material stage to their disposal as waste, in order to gain insights into the potential for minimizing their environmental impact. The results of research where the production of 600 ml plastic flower pot bottles required 28 grams of plastic resin per bottle, as well as energy for the production and transportation processes. Plastic packaging production produces defective products.

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Process improvement of hardening furnace (mapping) in tool industry -A case study You may also like Guided growth with aligned neurites in adult spiral ganglion neurons cultured in vitro on silicon micro-pillar substrates Prioritization of Lean Six Sigma Success Factors using Pareto Analysis Anand S Patel and Kaushik M Patel - A systematic literature review of lean six sigma Process improvement of hardening furnace (mapping) in tool industry -A case study

January 2024

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8 Reads

Viktorija Radoti

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Ana Bedalov

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Petar Drviš

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[...]

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Figure 9. Display widget predictions that are connected • Double-click on the Predictions widget to see the evaluation values that came out.
Figure 10. Display properties predictions in orange software
Dataset lenses display
Orange Software Usage in Data Mining Classification Method on The Dataset Lenses

December 2020

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2,425 Reads

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20 Citations

IOP Conference Series Materials Science and Engineering

Data Mining is a process that uses statistical, mathematical, artificial intelligence, and machine learning techniques to extract and identify useful information and related knowledge from various large databases. Decision tree is a very interesting classification method that involves the construction of a decision tree consisting of decision nodes which are connected by branches from the root node to the leaf node (end). The problem that will be examined in this study is about classification of dataset lenses obtained from using orange software. The method used in this paper is the method of classification process is performed on a decision tree using the orange software. Tree construction begins with the formation of roots (located at the top). Then the data is divided based on attributes that are suitable to be used as leaves. Decision rule information is to make decision rules from trees that have been formed.


Quality Assessment Using Quality Loss Function Method in PT. QRS

December 2020

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47 Reads

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3 Citations

IOP Conference Series Materials Science and Engineering

The process of production affects the quality of the products produced. Related to this, good quality control is needed to improve product quality. This quality control can be done by improving methods or production processes that reduce product quality. PT. QRS is one of the companies engaged in the manufacturing of zinc coated steel sheets. The problem in the company is to see if variation from the product can lead to additional cost or loss in the company. Based on these problems, it is necessary to calculate the losses due to variations in the dimensions of the product in which the company must pay to achieve the desired specifications. To find out the initial problem we can analyze with Taguchi’s Quality Loss Function. Based on calculations, it was found that the value of the process capability index for the long dimension obtained was Cp = 0,5556. From the calculation of the company’s loss data, it was obtained at Rp. 17.111.796/month.


A systematic literature review of lean six sigma

December 2020

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438 Reads

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8 Citations

IOP Conference Series Materials Science and Engineering

Competition in the industrial world lately is very tight. This intense competition requires companies to be able to compete very well. Companies must be able to provide good quality products that they produce. With the increasing competition, the supply of quality products has become a competitive advantage. Therefore, companies need to adopt competitive strategies that can improve the quality of their products, one of which is quality control. One of the quality control methods that can be used is Lean Six Sigma. Lean Six Sigma is a combination of two methods of improvement. Lean is a philosophy to reduce or eliminate unnecessary time, materials, and activities, while Six Sigma is a concept designed to increase overall effectiveness by defining, measuring, analyzing, improving, and controlling processes. Both the Lean’s philosophy and Six Sigma methodology focus on increasing bottom yields, increasing customer satisfaction, reducing defects and improving organizational performance. Therefore, this study has tried to review the current status of Lean Six Sigma from published research articles to reflect the purpose of this paper to compile the latest scenario for the deployment of Lean Six Sigma in various industries literature on Lean, Six Sigma and LSS (Lean Six Sigma).


Decision Support System of Family Karaoke Selection with Analytical Hierarchy Process Method using Super Decisions Software

December 2020

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81 Reads

IOP Conference Series Materials Science and Engineering

The rise of new and qualified karaoke venues is a place that many people often visit. In this journal, the family karaoke to be analyzed for comparison is K2 family Karaoke, NAV family karaoke, and Milo Family Karaoke. In the process of data processing, the method used is the method of Analytical Hierarchy Process (AHP) with Super Decisions Software. Based on the priority weight calculation for the service attribute where the karaoke is obtained that the reliability element is the highest value element of 0.35580. Furthermore, based on the weighted result of level 3 priority is found that the conformity element of the payment system offered has the highest value of the other element of 0.19973. Based on level 4 priority weighting results are obtained that the weight value for NAV Karaoke is the highest value of the other family karaoke is 0.61197.



Data defective product zinc roofing in 2019
Check sheet data of defective roofing product
Analysis Roofing Quality Control Using Statistical Quality Control (SQC) (Case Study: XYZ Company)

December 2020

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1,129 Reads

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11 Citations

IOP Conference Series Materials Science and Engineering

Quality is a dynamic condition related to products, services, people, processes and the environment that satisfy or exceeds expectations. Quality is the main factor for consumers in choosing products. The quality of products by company determine based on certain sizes and characteristics. XYZ company is a company engaged in Baja Lembaran Lapis Seng (BJLS) which produces zinc roofing. In order to survive in competitive market, improving quality and productivity of product is must for any company. Based on production on 2019 showed that there were 49,660 defective products out of 824,574 total production meaning that there were 5.95% of defective products that exceeded the companys tolerance limit of 2%. many products that defective products that cause repeat activities and losses finished products cause harm to the company. This study reports the application of statistical quality control techniques to ensure roofing quality and to minimize the presence of defective products. the results of the analysis with the P control map show that all data on the number of defects are still in the control limit with a Cp value of 0.9410, which is low improvements the product or process so able to continue to improve the quality of its products.


Quality Control Analysis on Poly cups Products Using Six Sigma Approach at PT “X”

December 2020

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587 Reads

IOP Conference Series Materials Science and Engineering

Quality in the manufacturing industry besides emphasize on the products produced, also need to be considered quality in the production process. Thus, the final product is defect free and there is no more waste to be paid handsomely because the product must discarded or reworked. PT. “X” is a company in the form of a Limited Liability Company in Deli Serdang Regency, North Sumatra. This limited liability company was established by several. PT. “X” is engaged in manufacturing namely producing poly cups. This company can produce 3900 poly cups box cartons / day. In a day can produce 352,800 poly cups/day. This quality control research was conducted at PT “X” with the product produced was poly cup. The study was conducted to determine the attribute defect of the poly cups with poly cups divided into 23 subgroups. Sampling is done by systematic sampling. Then, Six Sigma is one of the approaches that is used in this company quality control such as another make to stock company type.


Figure 2. Weibull graph on service time level
Ranking test for arrival frequency distribution
Ranking test for service level time distribution
Calculation of the number of optimum servers
Determining the Number of Optimum Servers in The XYZ Restaurant Queue System with Queuing Theory

December 2020

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472 Reads

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4 Citations

IOP Conference Series Materials Science and Engineering

Queue is a natural phenomenon that occurs when the demand for a service at a certain time exceeds the capacity of service at the same time. In this paper, the problem is solved using the queuing theory which is an analytical tool that is very helpful in solving queuing problems. This theory includes mathematical studies that produce important information needed in decision making with the help of forecasting various characteristics of the queue line. The queuing model in this restaurant queue system is (M / G / S). The current queuing system has System utility level (p) 52.23%, average time of customers in the queue (Wq) 0.4634 minute, The average time a customer in a system (W) 2.8074 minutes, Average Number of Visitors in the Queue (Lq) = 0.2104 ≈ 1 person, and Average Number of Visitors in the System (Ls) 1.2750 ≈ 1 person. The total waiting time on server 2 is below the maximum waiting time of 15 minutes and has the greatest system utility level, thus the optimum number of servers chosen is server 2 which is already optimum.


Citations (19)


... Steam turbine power plant is a complex system comprising various systems, from combustion chamber, heat recovery steam generator (HRSG), steam turbine and generator operating simultaneously and continuously 24 hours to be available on demand [3,4] therefore there is a vast volume of operation and maintenance data recorded every day. By this reason, optimal maintenance planning is then important tool to achieve its reliability, availability and maintainability [5]. Preventive maintenance is basically performed in power plant maintenance due to fewer interruptions to critical operations and fixed schedule maintenance tasks because PM is a deterministic time-based maintenance activity [6,7,8]. ...

Reference:

RAM-based Data Analytics for Power Plant Case Study: Steam Power Plant in Thailand
The Fuzzy Failure Mode and Effect Analysis (FMEA) Method to Improve Roofing Product’s Quality (case study : XYZ Company)

IOP Conference Series Materials Science and Engineering

... Diagram Pareto adalah yang dapat mengurutkan masalah berdasarkan masalah yang paling sering terjadi dan juga menunjukkan pengaruh permasalahan tersebut terhadap keseluruhan. Diagram Pareto digunakan untuk mencari sejumlah permasalahan yang memberikan kontribusi besar terhadap keseluruhan permasalahan (Ishak et al., 2020). Hasil dari Diagram Pareto kemudian dilanjutkan dengan perhitungan level sigma. ...

Reducing waste to improve product quality in the wooden pallet production processby using lean six sigma approach in PT. XYZ

IOP Conference Series Materials Science and Engineering

... FMEA tools have become standard practice in companies in countries all over the world, in sectors ranging from aerospace, and electronics to automotive, it is also used in the food industry, the energy sector, and medical and pharmaceuticals. (Ishak et al., 2020;Mascia et al., 2020). ...

Implementation Statistical Quality Control (SQC) and Fuzzy Failure Mode and Effect Analysis (FMEA): A Systematic Review

IOP Conference Series Materials Science and Engineering

... This methodology is applied to devise a two-stage parameter optimization scheme, utilizing nonlinear optimization algorithms to identify the optimal joint parameter design values for space and time factors [8]. Khawarita Siregar et al. used Taguchi's quality loss function for quality assessment to calculate the loss due to product dimensional variations, determining the long-dimensional process capability index required for a company to meet the desired specifications [9]. Mao et al. conducted research on the reliability issues of components. ...

Quality Assessment Using Quality Loss Function Method in PT. QRS

IOP Conference Series Materials Science and Engineering

... The steps taken in making a Pareto diagram are to sort each type of defect from the largest number of defects to the smallest. Then calculate the percentage of defects and the cumulative percentage of each type of defect (Ishak, 2020). ...

Analysis Roofing Quality Control Using Statistical Quality Control (SQC) (Case Study: XYZ Company)

IOP Conference Series Materials Science and Engineering

... To determine the turning point on the graph, two data are used, namely the solar elevation angle data and the mpsas value, then the mpsas data is approached with the exponential function obtained using formula (1) of normal distribution [33], [34]. To simplify the calculation, the solver menu is used, so that the prediction function gets an optimal minimum difference from the original data. ...

Distribution Testing On The Average Room Occupancy Rate Of Hotels By Province In 2013-2017

IOP Conference Series Materials Science and Engineering

... The workflow in Orange Datamining Software begins with a File widget to load the dataset, which is then passed through a Select Columns widget to choose relevant features [62] [63]. ...

Orange Software Usage in Data Mining Classification Method on The Dataset Lenses

IOP Conference Series Materials Science and Engineering

... The combination of these methods can be used in overcoming various weaknesses of waste reduction methods that have been employed in previous studies. Based on latest studies ( [7]; [8]; [9]; [10]; [11]; [12]; [13]), a combination of the Waste Assessment Model and Fuzzy FMEA methods has never been carried out on Lean Six Sigma, suggesting that there is a difference between the proposed models that we designed and those from previous research. ...

Quality Control Analysis With Lean Six Sigma Approach and Weighted Product Method (case study: XYZ Company)

IOP Conference Series Materials Science and Engineering

... Lean Six Sigma is a method that seamlessly integrates data-driven Six Sigma methodology with lean principles, focusing on simplifying processes, eliminating waste, and enhancing efficiency within the main components of Lean and Six Sigma. Emphasizing customer satisfaction and continuous improvement is also integral (Ishak et al., 2020). Implementing Lean Six Sigma can potentially boost process cycle efficiency by up to 70% (Guleria et al., 2022). ...

A systematic literature review of lean six sigma

IOP Conference Series Materials Science and Engineering

... The growing population, including in Indonesia, requires people to develop a queuing culture, especially in places where people have crowded activities. Queues will occur if the demand for a service exceeds the available order [1]. Every company wants to fulfill customer satisfaction by providing the best service. ...

Determining the Number of Optimum Servers in The XYZ Restaurant Queue System with Queuing Theory

IOP Conference Series Materials Science and Engineering