ANGGI FITRIYANSYAH LUBIS

Sebuah elemen hingga tiga dimensi dari analisis Pushover Jembatan nonlinier untuk jembatan Beton Bertulang (RC) bentang pendek dengan penampang pilar melingkar dimodelkan untuk menyajikan efek interaksi struktural tanah (SSI). Model elemen struktur Pushover Jembatan meliputi pemodelan pegas pondasi linier, dan pemodelan pilar RC nonlinier. Makalah ini berhasil menyajikan efek SSI dari analisis pushover nonlinier jembatan RC bentang pendek untuk menentukan pengaruh signifikan terhadap karakteristik dinamis dan kapasitas perpindahan kinerja jembatan RC bentang pendek; yang meningkat dalam kisaran 11% hingga 20% dibandingkan dengan analisis pushover dasar jembatan tanpa efek SSI. Hasil menunjukkan kekakuan jembatan berkurang karena efek SSI pada dukungan jembatan untuk jenis tanah yang lebih fleksibel yang menghasilkan perpindahan besar, dengan geser dasar yang lebih sedikit di pilar jembatan dan pijakan dengan persentase rata-rata 12% dan 18%, yang penting untuk evaluasi struktural untuk pembangunan jembatan baru serta evaluasi pekerjaan perkuatan dan perbaikan jembatan eksisting.

Pemodelan dan analisis seismik struktur jembatan telah menjadi evolusi besar selama beberapa dekade terakhir yang terkait langsung dengan perkembangan pesat komputasi digital. Analisis statis dan dinamis dari sistem jembatan mengalami terobosan besar ketika teknik elemen hingga dikembangkan. Di masa lalu, prosedur analisis elastis yang digunakan untuk penilaian struktur jembatan tidak cukup untuk tindakan inelastis yang terjadi. Analisis dinamik nonlinier menjadi penting untuk penilaian struktur jembatan, namun memakan biaya yang mahal. Untuk itu, analisis statik nonlinier (pushover) menjadi alat perilaku seismik inelastis yang lebih disukai dalam evaluasi struktur jembatan karena biayanya yang rendah dan memakan waktu.

Dalam banyak penelitian sebelumnya tentang jembatan yang memasukkan SSI serta inelastisitas di dermaga jembatan menghasilkan pendapat yang bertentangan tentang peran inelastisitas struktural pada permintaan seismik.

Dalam analisis jembatan konvensional, alasnya dianggap sebagai alas tetap; investigasi yang sangat terbatas difokuskan pada identifikasi SSI pada jembatan yang menopang pada pondasi dangkal. Tingkat kelenturan tanah penyangga akan tergantung pada jenis tanah dan parameter tanah mulai dari tanah sedang hingga tanah lunak. Ini mengurangi kekakuan keseluruhan jembatan yang mengakibatkan peningkatan berikutnya dalam periode alami sistem dan respons keseluruhan diubah. Interaksi struktur tanah akan berpengaruh signifikan terhadap kurva kapasitas keseluruhan jembatan pada analisis pushover, yang tercermin pada modus keruntuhan superstruktur jembatan, [4] , [5] , dan [6] .

Pada penelitian sebelumnya, [5] menunjukkan bahwa pengaruh SSI pada jembatan lebih kuat dipengaruhi oleh sifat struktur nonlinier dari komponen struktur bawah jembatan dibandingkan dengan sifat tanah. Namun, kemajuan dalam kemampuan komputasi efek interaksi struktur tanah pada analisis statis nonlinier (analisis pushover) telah sepenuhnya tercermin dalam peningkatan desain seismik dari penilaian kerentanan baru atau dan retrofit struktur jembatan yang ada. alat analisis yang tersedia saat ini membantu proses perancangan baru atau perkuatan struktur jembatan yang ada yang terkena gempa dengan mempertimbangkan SSI pada analisis pushover pilar jembatan untuk meningkatkan kurva kapasitas pilar yang mencerminkan penilaian struktural dan penguatan jembatan yang ada.

Kota Cabanatuan dijuluki sebagai “Ibukota Roda Tiga Filipina”. Sepeda roda tiga merupakan Moda Alternatif kendaraan roda tiga yang digunakan untuk mengangkut orang. Cabanatuan memiliki sekitar 30.000 sepeda roda tiga Moda Alternatif bermotor empat langkah yang terdaftar dengan bahan bakar gas. Operasi becak di Kota ini telah menjadi sumber penghidupan bagi sekitar 10.000 keluarga. Jumlahnya meningkat pesat meskipun persaingan meningkat dan pendapatan bersih harian menurun dan dampak buruk yang ditimbulkannya terhadap lingkungan. Studi ini menganalisis aspek yang berbeda dalam adopsi E-trikes (becak listrik) sebagai moda sistem transportasi umum menggantikan becak bermotor di kota. Kerangka konseptual pembangunan berkelanjutan digunakan untuk menganalisis data. Metode akuntansi dasar dalam menentukan laba atas investasi dan periode pengembalian digunakan untuk membandingkan biaya dan pengembalian antara moda transportasi saat ini dengan penerapan E-trike. Pengumpulan data menggunakan wawancara, kuesioner survei dan diskusi kelompok terfokus. Tiga bidang keberlanjutan yang diukur dalam studi ini adalah ekonomi, sosial-politik dan lingkungan. Studi menunjukkan bahwa dari 412 pengemudi-operator roda tiga yang dipilih secara acak, mayoritas setuju untuk beralih dari sepeda roda tiga bermesin ke E-trike. Namun, biaya E-trike menghalangi adopsi dan implementasi penuh oleh Pemerintah Kota. Isu politik juga menjadi pertimbangan utama karena perpindahan kerja akan segera terjadi di antara para pemangku kepentingan setelah adopsi mode ini terjadi. Di sisi lain, E-trike terbukti berkelanjutan dalam jangka panjang baik dari sudut pandang operator maupun masyarakat pengendara. Makalah tersebut merekomendasikan agar peraturan kebijakan ditetapkan, diadopsi, dan dilaksanakan oleh unit pemerintah daerah sebagai tanggapan terhadap Filipina Cleaner Air Act.

Penggunaan becak telah menjadi moda transportasi di sebagian besar kota berkembang di dunia [1] . Sepeda roda tiga (bermotor dan tidak bermotor) adalah moda transportasi utama dalam kota [2] meskipun dianggap sebagai sektor informal, dampaknya terhadap transportasi dan manajemen tidak perlu dipertanyakan lagi [3] . Di Cina, sepeda roda tiga yang berfungsi terus menyediakan kebutuhan sosial dan ekonomi meskipun ada ancaman akan dihapus karena mobilitas neoliberal yang berkembang di dalam kota [4] . Di India, moda transportasi yang sama digunakan oleh masyarakat umum yang menimbulkan tantangan besar bagi pertumbuhan penduduk tentang bagaimana pemerintah akan menjaga kualitas udara yang baik [5] . Di Nigeria, penggunaan sepeda roda tiga bermotor didorong di dalam batas kota untuk mengurangi kemacetan lalu lintas [6] . Di Metro Manila, Filipina, moda transportasi umum yang menggunakan jalan sekunder menempati kursi depan dalam pembuatan kebijakan lokal dalam pemerintahan lokal dan pembangunan perkotaan [7] . Di Kota Cabanatuan Filipina, moda transportasi ini mencakup lebih dari 50% alat angkut mengingat terbatasnya rute yang dapat ditempuh oleh jeepney [8] .

Di Filipina, roda tiga listrik atau E-trike sama dengan roda tiga dalam hal konfigurasi atau hampir mirip dengan becak tradisional yang beroda tiga, dan dapat mengangkut beberapa penumpang dan tergantung pada desain bodi dan kapasitas kendaraan. mesin bermotor. E-trike dijalankan oleh listrik sedangkan yang terakhir adalah gas-makan. Desain khas yang populer di Filipina adalah sespan yang dipasang di samping sepeda motor untuk mengangkut penumpang.

Simulation of wind power with front-end converter into interconnected grid system, In the growing electricity supply industry and open access market for electricity worldwide, renewable sources are getting added into the grid system. This affects the grid power quality. To assess the impact on grid due to wind energy integration, the knowledge of electrical characteristic of wind turbine and associated control equipments are required. The paper presents a simulation set-up for wind turbine in MATLAB / SIMULINK, with front end converter and interconnected system. The presented control scheme provides the wind power flow to the grid through a converter. The injected power in the system at the point of common coupling is ensured within the power quality norms.

Generation of electricity from wind is the fastest growing energy technology in the world. India is in the 4th rank and has a renewable energy gross potential installed of 7855 MW as on 2006.With increasing wind power production, it is important for grid owners, to predict the grid interaction of wind turbine in advance. Some grid simulation packages like power system simulator are used for power system behavioral studies. Models of new types of generating units, like wind turbine have to comply with the requirement. Considering wind turbine generating system operation in electric power system, it is necessary to utilize the steady state model for analysis, related to load flow, short circuit calculation, power quality assessments, etc. The electric utility grid system cannot accept connection of new generation plant without strict condition, due to the real power fluctuation and reactive power generation of wind plants. Therefore the penetration of wind power in grid implies taking care of power quality issues like voltage variation on grid, switching operation of wind turbine (Reid, 1996). Today grid connected wind turbines are equipped with power converter systems. The wind–generation system interconnected with power system as shown in Figure .

In modern wind turbine system, power is exchanged with grid through a dedicated power interface so as to improve the power quality norms and it should compensate for harmonics and reactive power in the system. The typical system is simulated for practical condition in power system and simulated results are presented. The proposed control keeps the unity power factor at the point of common coupling (PCC) and allows the system voltage be stable while compensating the reactive and real power demand of the load. The dynamics of the system and control action is simulated with the detail model of wind generator with front end converter system. This simulation is carried out in SIMULINK with power system block set.

IDEF method-based simulation model design and development framework to provide an IDEF method-based integrated framework for a business process simulation model to reduce the model development time by increasing the communication and knowledge reusability during a simulation project. In this framework, simulation requirements are collected by a function modeling method (IDEF0) and a process modeling method (IDEF3). Based on these requirements, a common data model is constructed using the IDEF1X method. From this reusable data model, multiple simulation models are automatically generated using a database-driven simulation model development approach. The framework is claimed to help both requirement collection and experimentation phases during a simulation project by improving system knowledge, model reusability, and maintainability through the systematic use of three descriptive IDEF methods and the features of the relational database technologies. A complex semiconductor fabrication case study was used as a testbed to evaluate and illustrate the concepts and the framework. Two different simulation software products were used to develop and control the semiconductor model from the same knowledge base. The case study empirically showed that this framework could help improve the simulation project processes by using IDEF-based descriptive models and the relational database technology. Authors also concluded that this framework could be easily applied to other analytical model generation by separating the logic from the data.

Simulation is one of the most widely used decision aid tools due to its power, flexibility, and robustness. Particularly the discrete event simulation (DES) can model and analyze the behavior of many real life processes such as business processes, supply chain, and manufacturing processes. However, as Ryan et al. pointed out (2006), the simulation modeling often becomes a heavy programming task with the essence of the system being modeled lost in the detailed programming codes. In this way, the essence of the system is visible only to the code developers. This could create several potential problems for those who are involved in a simulation project. For example, it may create a serious information reusability problem. A simulation model is an abstracted representation of a real system to solve specific problems. Hence the information collected and extracted from the real system should be systematically represented and stored for future reuse in the form of systematic descriptions and formats. It may also cause a communication problem between developers and users. Typically users are domain experts who want to experiment with the simulation model to solve domain specific problems. This task requires frequent parameter changes and modification of the model. However, the heavy codes add difficulty to the proper management of this task. If we consider a simulation model development as a project, and if we have a structured systematic tool to support the simulation project, we believe that these problems could be managed. Sheppard (1983) proposed a widely cited “40-40-20” simulation model development time rule which states that analyst’s time should be distributed as follows for a successful simulation project: (1) 40% to requirement collection phase such as problem formulation, project planning, conceptual model development, and data collection; (2) 20% to model translation phase; (3) 40% to experimentation phase such as model verification, validation, implementation, and interpretation. Hence, for successful implementation of any simulation project, it is particularly important to have a right approach to the requirement collection and the experimentation phases. Hence, this paper intends to provide an integrated framework for those two phases in a simulation project.

The process description methods could play an important role in the simulation requirement collection phase. Although many process design, analysis and modeling (DAM) methods have been developed, using these methods in isolation – non-methodological approach – often fails to capture critical system behaviors due to the complexities and component interactions within the system. A methodological approach – systematic usage of a suite of methods – has a greater chance of success at representing critical system behaviors since it can account for diverse aspects of DAM activities such as information, function, and process interactions by a systematic and integrated usage of methods. IDEF (Integrated DEFinition) is a suite of descriptive modeling methods within which several different modeling languages are defined to describe systems from different perspectives. First, since IDEF is a well defined suite, it is considered to be easier to implement a methodological approach with the IDEF suite rather than with a completely different set of methods. Second since it is a descriptive modeling method, it could easily abstract and capture the essence of the system. In a typical simulation project, a project team consists of many team members such as system analysts, developers and domain experts. The system analysts collect and refine requirements with assistance from domain experts. This is an iterative communication process among all members. The ‘descriptiveness’ of IDEF methods could make this communication process easier and smoother than any other non-descriptive methods. For these reasons, IDEF methods have been a continued research subject.

The first category of the IDEF method related research attempted to build a generic and conceptual descriptive model using IDEF suites in a specific domain (Ang et al., 1994; Zhang et al., 1996). Another category proposed a way to generate an analytical model from a specific IDEF model. For example, an IDEF3 method has been used to generate simulation models using Witness simulation software (KBSI, 1995) and using Arena software (Resenburg et al., 1995). Jeong et al. (2008) developed a scheme to integrate the IDEF3 with a general open queuing network where IDEF3 works as a knowledge repository. The third category employed multiple IDEF methods and attempts to reuse common system knowledge among the different IDEF methods. For example, Lingzhi et al. (1996) proposed a scheme to integrate IDEF1 with IDEF0 for a computer integrated manufacturing information system design. Chen et al. (2004) also proposed a scheme to develop the enhanced IDEF1 information model based on the IDEF0-based process information, which could serve as a base representation for an information model. This paper covers both the second and the third category together. It is an extension of Cho et al. (1999), KBSI (1995), and Chen et al. (2004) in that it attempts to provide an integrated framework of IDEF method-based simulation model design and development to help a successful simulation project.

Fuzzy containers allocation problem in terminals has attracted lots of research works due to practical & theoretical importance in transportation literature. In this paper, we developed a fuzzy mathematical programming model for solving problem of allocating the containers in terminal area. The objective is minimizing the total distance traversed by the containers from the ship to the terminal area they are assigned. Fuzzy set concepts are used to treat imprecision regarding the distances between berth and terminals area, number of containers in an arrived ship and estimation of available area in each terminal at a port. We proposed two types of models for optimistic and pessimistic situations. The proposed models have been coded in LINGO8.0 solver and a numerical example has been solved for illustration purpose. The full analysis of the proposed models can cause an optimum allocation of containers of several ships to different terminals of berths in fuzzy environment.

Nowadays maritime transportation has an essential role in economies as it permits goods exchange between far-off countries. Application of containers is a proper technology for transporting freight, especially on long maritime routes. There are a large number of ports around the world, ranging from single berth locations handling a few tons a year to multipurpose one which handle up to several million tons a year. Over the last decades the use of containers for general cargo has extended extremely.

Containers are large metal modules made in universal standard dimensions and measured in multiples of twenty feet called “twenty foot equivalent units” (TEUs). Containers require less product packaging. They help reducing defect, and they result in higher productivity during the handling process. Moreover containers allow for inter-modal transportation because transshipment between ships, trucks or trains is easily performed (Caramia & Dell’Olmo, 2008). Containers allocation in terminals has attracted lots of research works due to practical & theoretical importance in transportation literature. Several extensions of the problem have been considered in this area. The variety of research work about container allocation, berth allocation problem (BAP) or any related topic is impressive. Researchers have tried to map their assumptions about the problem and have developed a suitable procedure like mathematical programming, heuristic/ meta-heuristic and etc. The emerged problems in this family have either theoretical or practicaloffspring and are mainly categorized in NP-Hard class.Some of the last research works in this area can be outlined as: Hansen et al. (2008), Liang et al. (2008), Imai et al. (2008), Canonaco et al. (2008), Imai et al. (2008), Imai et al. (2007), Cordeau et al. (2007), Wang and Lim, (2007), Li et al. (2007).

To our best knowledge, there are few research works in fuzzy BAP, although real world problems are faced with ambiguous parameters which could efficiently be modeled through fuzzy concepts. In this paper, we define and attack Containers Allocation Problem in Maritime Terminals in fuzzy environment. The distances between berth and terminal area, number of containers in an arrived ship and estimation of available area in all terminals of port are assumed to be positive Trapezoidal Fuzzy Numbers (TrFNs) which will be define in section 2. The objective is minimizing total traversed distance by the containers from the ship to the terminals area they are assigned in an ambiguous environment. The following sections of this paper are arranged as below. Some well-known and main arithmetic operator in fuzzy environment which is used in this paper and their associated notations are introduced in section 2. Section 3 is allocated to define the problem scope and assumptions. Crisp model and proposed fuzzy model are also represented in section 3. Experimental results are outlined in section 4. Finally in the 5th section the paper will be ended with a brief summery and conclusion.

Process Simulation and Modeling is special issue of the Journal of Industrial Engineering and Management is focused on new trends in Process Simulation and Modeling.

This special issue of the Journal of Industrial Engineering and Management is focused on new trends in Process Simulation and Modeling.

Many business processes are so complex, interconnected and subject to variability. For those reasons, it is hard to understand the components evolution and interactions within the business processes without a dynamic model. Simulation and modeling approach is a good choice to predict processes performance, to compare alternatives and to establish the effect of several scenarios on performance. Moreover, if a process does not yet exist, or company is considering a new implementation, a simulation model can give a clue how well the proposed process will perform. In addition, process simulation and modeling is a growing and exciting research field.

In general terms, simulation is one of the most commonly used methodologies employed in Information Systems and Operations Management research. As Simulation: Transactions of The Society for Modeling and Simulation International shows, the methods and applications of modeling and simulation in both well-established and emerging areas include the fields of, but are not restricted to:

• Computer Science: Computer networking and communications, high performance computers, real-time systems, mobile and intelligent agents, simulation software, and language design.
• Engineering: System engineering and design, aerospace, traffic systems, microelectronics, robotics, mechatronics, and air traffic.
• Physical and Life Sciences: Chemistry, physics, biology, medicine, biomedicine, sociology, and cognition.

A simulation is simply an imitation of the operation of a real-world system or process for purposes of its evaluating. Over the last thirty years, computer simulation has enjoyed a great deal of popularity in the manufacturing, production, logistics, service, and financial industries, just to name a few fields of application.

In this sense, simulation is a powerful tool if understood and used properly. Simulations are often used to analyze systems that are too complicated to analyze with analytic methods such as calculus, standard probability and statistics, or queuing theory. An especially interesting feature of simulation is its ability to allow the experimenter to analyze and compare certain scenarios quickly and efficiently.

The focus of this special issue of the Journal of Industrial Engineering and Management is to publish high quality research papers that either addresses significant issues related to the use of simulation in process research. The goal of this special issue is on bringing together researchers and practitioners from the areas of process management, computational intelligence, decision support, simulation and modeling. The technical objective is to exchange ideas and techniques from those areas as well as to establish a framework for the development of methodologies that integrate decision support, process management, technology, simulation and modeling.

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