INTEGRASI FUZZY LOGIC DAN MINIMAL REPAIR DALAM PENJADWALAN PERAWATAN MESIN UNTUK MENGOPTIMALKAN LIFETIME MESIN PRODUKSI

Production machines are one of the main assets of the company. The machines may not be the perfect level of reliability at all times. Over time, a machine will have breakdown and the breakdown may occur is uncertain. Uncertainty breakdown machine would cause losses greater than the scheduled maintenance. Therefore, it is necessary to scheduling machine maintenance. The machine maintenance will restore and or maintain the condition of the machine at particular state. It depends on the quality of machine maintenance. The better rate of quality maintenance as a result of the maintenance machine, the machine lifetime production machine will be more optimal. The concept of fuzzy logic and minimal repair is an approach that can accommodate uncertainty and the quality of maintenance. In this research, the two concepts will be integrated to scheduling maintenance of production machine. Moreover, it will be built also interface for user interface to facilitate the use of this software. This research uses a case study of PT Holcim Indonesia, Cilacap plant and focus on finish mill area, especially Ball Mill machine. This is because these areas have the availability and MTBF lower than other area that is 92.27% and 21.02 hours. This means that in these areas often have breakdown. When integrate, minimal repair is used as one of the inputs in the fuzzy model in addition to the reliability and cost. The results of this research found the period of machine maintenance 5 times in 1 year with savings of almost 11,78% of the cost of maintenance has been done now. Scheduling maintenance of the machine is the first for maintain Motor, and the second for Diaphragm, third for Temperature Bearing, Bolt Liner, Bolt Man Hole, and Vibration Bearing, fourth for, Mill Chamber and Ball Mill and last for Inlet Ball Mill. Keywords: Scheduling Machine Maintenance, Breakdown, Lifetime Optimization, Fuzzy Logic, Minimal Repai

ANALISIS SENSITIVITAS PADA METODE MULTIPLE CRITERIA DECISION MAKING (MCDM) UNTUK PENENTUAN KONTRAKTOR

Knockout and lowest price are methods commonly used in selecting contractor in Indonesia. The weakness of this method is often arising problems on owners� side such as poor quality project, maintenance cost overrun and not economical for long term solution. Multiple Criteria Decision Making (MCDM) method is a method that can evaluate the winning bidder with a lot of criteria. From owner�s project perspective, a good MCDM method should robust and insensitive means that it is not affected by variations of a variable changing. From the contractor�s perspective, the desired evaluation method is a method that is sensitive to changes in the company's data. This study aims to analyze sensitivity of MCDM method. AHP, VIKOR, TOPSIS, PROMETHEE and ELECTRE are the most commonly used and represent the group of the MCDM method. The research object is the tender \"X\", the company which passed administrative and technical requirements and the tender committee of construction as respondents. Pair wise comparison and weighting of importance are used to get the weight as an input for five methods of MCDM. Then, sensitivity analysis is performed on the number of respondents and company data. Sensitivity analysis for company data uses fractional factorial design and Taguchi method. Those methods are performed for combination of data changes which are amount of equipment owned by company, work experience and education level of key personnel that will change the offering price. Fractional factorial design is used to reduce factors so that only significant influent factors that are used as inputs in Taguchi method. Taguchi method is used to sensitivity analysis and Signal to Noise Ratio (SNR) is to measure its sensitivity. MCDM method processing was found that all methods of MCDM (AHP, VIKOR, ELECTRE, PROMETHEE and TOPSIS) generate CV JA as the winner, but AHP produces different ranking for the second and third compared with others. Based on the sensitivity analysis on the weight changes produced by that method of AHP and VIKOR are sensitive to changes in weight. Based on sensitivity analysis to changes in the company's data concluded that VIKOR method is the least sensitive to changes in company�s data while PROMETHEE method is the method most sensitive to changes in the company's data. Keywords: Multiple Criteria Decision Making (MCDM), Sensitivity Analysis, Contractor Selections, Signal to Noise Ratio (SNR), Design of Experiment

PENENTUAN KEBUTUHAN SILINDER GAS BERDASARKAN PENDEKATAN STATISTICAL DISTRIBUTION (Studi Kasus pada Perusahaan Minyak dan Gas Multinasional)

Supporting part inventories in oil and gas company are the things that need attention. When the unexpected condition cause an increasing demand but there�s no enough inventory available in warehouse, problems may occur. Gas cylinder is one of example that categorized as supporting inventory. Gas cylinders are used to place the gas. When volume of the gas diminish, refill needed. Process to refill the cylinder with specific gas is not that simple. It needs a time to ship the gas cylinder to the vendor which is located far from the operation field, and send them back to be stored in warehouses then. To minimize the stock out problem, we have to identify and model the demand, so we can predict it in the future. Prediction is needed to improve inventory planning in order to increase the availability of stock. The study began by identifying patterns of demand that occurred during the last five years, and then implementing statistical distribution approach to modeling the fluctuation, so we can predict demand conditions that will occur in the next period and make an inventory planning to meet future demand. These results indicate a pattern of declining trend in oxygen and acetylene gas and random patterns on other types of gases. Further statistical distribution approach using exponential distribution, Weibull and Lognormal will provide the estimated value of demand and supply to note that 95% service level can be achieved

METAHEURISTIC-BASED FUZZY C-MEANS ALGORITHM FOR APPAREL SIZING SYSTEM

Sizing system is essential for apparel design and production. Accurate size of apparel is related to customer satisfaction and manufacturing. Several researches had been proposed to create sizing system. This study aims to develop a new sizing system for anthropometry data using novel data mining approach. This study employs metaheuristic-based clustering techniques to determine a new standard sizing system for apparel industry. Through measuring anthropometry of 912 objects (598 males and 304 females) aged between 18 and 25, this study proposes a sizing system for Indonesian adult with seven variables, hip width, arm length, waist width, bust width, back-waist length, back-rest width, and stature. There are two stages for the proposed method. The first stage employs principal component analysis (PCA) for feature extraction. Then, several metaheuristicbased techniques will be employed to find the best sizing system which fit to the population and hybridized with fuzzy c-means. The computational result indicated that five groups of size are feasible for the current data. In addition, based on the aggregate loss the proposed model has a good accuracy and the result can be used as a size recommendation to specify the right size for the customers

PENENTUAN TIPE SUARA ALARM T-3 DAN INTENSITAS JUST NOTICABLE RESIDENTIAL FIRE ALARM PADA AKTIVITAS MENONTON FILM

Fire alarm is one of the important safety equipment at home. In Indonesia, there were four family members of different ages have different hearing abilities in one house. So that, it takes various intensity detection. This study used three factors: the type of alarm, age, and place. Alarm type is divided into intermittent, sweep, and alternating while age categories divided into children, adults, and seniors. Place factor is for adults between resident and laboratories. Response used is just noticeable intensity in dB, response time, and number of running. Noise movie is set at 70 dB and reception distance is 1.9 times television diagonal. Movie is chosen as background noise. Total of 10 people from each age category is used as a respondent. The method used is transformed up-down method with two positive responses and two negative responses. Alarm T-3 which are easily detected for residential fire alarm is intermittent type with a minimum level of 42.75 dB. The response time required to detect intermittent alarms in children is 2.31 seconds, 2.13 seconds for adults, while seniors are 2.59 seconds. Intermittent type which has a square pattern can provide a sense of discomfort and disturbance effects on the listener. The older a person the ability to hear is declining, so is in giving response. In addition, seniors often do errors when the concentration is divided so that the number of required running is increase. Differences of place in the study having no significant effect on the response