Central Authority–Controlled Air Traffic Flow Management: An Optimization Approach

Despite various planning efforts, airspace capacity can sometimes be exceeded, typically because of disruptive events. Air traffic flow management (ATFM) is the process of managing flights in this situation. In this paper, we present an ATFM model that accounts for different rerouting options (path rerouting and diversion) and preexisting en route flights. The model proposes having a central authority to control all decisions, which is then compared with current practice. We also consider interflight and interairline fairness measures in the network. We use an exact approach to solve small- to medium-sized instances, and we propose a modified fix-and-relax heuristic to solve large-sized instances. Allowing a central authority to control all decisions increases network efficiency compared with the case where the ATFM authority and airlines control decisions independently. Our experiments show that including different rerouting options in ATFM can help reduce delays by up to 8% and cancellations by up to 23%. Moreover, ground delay cost has much more impact on network decisions than air delay cost, and network decisions are insensitive to changes in diversion cost. Furthermore, the analysis of the tradeoff between total network cost and overtaking cost shows that adding costs for overtaking can significantly improve fairness at only a small increase in total system cost. A balanced total cost per flight among airlines can be achieved at a small increase in the network cost (0.2%–3.0%) when imposing airline fairness. In conclusion, the comprehensiveness of the model makes it useful for analyzing a wide range of alternatives for efficient ATFM.

Recent Trends and Repercussions in Civil and Criminal Justice Systems

The reform of civil and criminal justice systems is a contentious issue and has become the top priority for the international community in re-establishing the rule of law. The justice systems in many common law jurisdictions are perceived to be ‘in crisis' deformed by exorbitant delay, cost, and complexity in proceedings. The level of resources engulfed in the judicial system has very little or no impact on judicial performance. Comparative and comprehensive analysis of the law not only leads to a better realization of the foreign laws, but also it aids with law unification. This chapter will attempt to highlight the issues in the civil and criminal justice system and comparatively analyze the scenario in England, Singapore, and India. In furtherance, the authors explore the possible methods to curb the delay in justice systems and canvas the modern trends in civil and criminal justice policy.

Fast Algorithms for Basic Supply Chain Scheduling Problems

A basic supply chain scheduling problem in which the orders released over time are to be delivered into the batches with unlimited capacity is considered. The delivery of each batch has a fixed cost D, whereas any order delivered after its release time yields an additional delay cost equal to the waiting time of that order in the system. The objective is to minimize the total delivery cost of the batches plus the total delay cost of the orders. A new algorithmic framework is proposed based on which fast algorithms for the solution of this problem are built. The framework can be extended to more general supply chain scheduling models and is based on a theoretical study of some useful properties of the offline version of the problem. An online scenario is considered as well, when at each assignment (order release) time the information on the next order released within the following T time units is known but no information on the orders that might be released after that time is known. For the online setting, it is shown that there is no benefit in waiting for more than D time units for incoming orders, i.e., potentially beneficial values for T are 0<T<D, and three linear-time algorithms are proposed, which are optimal for both the offline and the online cases when T≥D. For the case 0<T<D an important real-life scenario is studied. It addresses a typical situation when the same number of orders are released at each order release time and these times are evenly distributed within the scheduling horizon. An optimal algorithm which runs much faster than earlier known algorithms is proposed.

ANALISIS MODEL ESTIMASI NET PRESENT VALUE PADA PENJADWALAN PENAMBANGAN TERBUKA BATUBARA PIT 11 PT ARUTMIN INDONESIA SITE KINTAP KABUPATEN TANAH LAUT

PT Arutmin Indonesia merupakan salah satu perusahaan yang bergerak dibidang industri pertambangan. PT Arutmin Indonesia memiliki kontrak PKP2B dengan umur kontrak yang berakhir pada 2 November 2020. Penelitian dilakukan disalah satu area PKP2B PT Arutmin yaitu pit 11 di site Kintap. Pada pit 11 akan dilakukan eksploitasi dengan melakukan penjadwalan penambangan yang dipertimbangkan berdasarkan analisis kriteria ekonomi. Analisis kriteria ekonomi pada pit 11 digunakan analisis kriteria net present value (NPV).Pada penelitian proyek penambangan pit 11 terdiri atas dua general description yaitu penjadwalan penambangan dan analisis net present value. Penjadwalan penambangan dikerjakan dengan bantuan aplikasi perangkat lunak Xpac 7.14, dimana penjadwalan disimulasikan menjadi 2 simulasi berdasarkan penempatan fleet untuk menentukan penjadwalan penambangan berdasarkan target produksi. 2 simulasi penjadwalan akan diestimasikan berdasarkan forecast rain delay menjadi 3 skenario yaitu skenario 1 pada saat minimum rain delay, skenario 2 pada saat average rain delay, dan skenario 3 maximum rain delay. Dari masing-masing simulasi penjadwalan penambangan akan didapat target produksi batubara, volme overburden dan penentuajn jarak pengangkutan yang akan dianalisis tigkat keekonomisannya berdasarkan kriteria net present value dengan pertimbangan biaya (cost) penambangan dan pendapatan (revenue) dengan komoditas harga batubara (coal price) dan discount rate yang berlaku di PT Arutmin Indonesia. Dengan menggunakan SImulasi 1, penambangan akan berlangsung selama 10 bulan (skenario 1 dan 2 ), dan 11 bulan (skenario 3). Adapun bila menggunakan Simulasi 2, penambangan akan berlangsung selama 12 bulan (skenario 1), 14 bulan (skenario 2) dan 15 bulan (skenario 3Hasil Nilai NPV dari masing-masing simulasi 1 dan 2 didapat untuk skenario 1 nilai NPV yaitu $ 29,608,151.48 skenario 2 besar NPV yaitu $29,589,419.87 , dan skenario 3 besar NPV yaitu $ 29,552,139.84. Sedangkan hasil dari simulasi 2 untuk skenario 1 didapat besar NPV yaitu $ 29,552,139.30 , skenario 2 besar NPV yaitu $ 29,271,760.24 dan skenario 3 besar NPV yaitu $ 29,150,450.08. Berdasarkan hasil perbandingan, nilai NPV terbesar akan didapatkan bila penjadwalan penambangan dilaksanakan dengan Simulasi 1 yaitu penjadwalan produksi dilakukan dengan menempatkan 2 fleet di pit 11A kemudian dilanjutkan 2 fleet di Pit 11BKata-kata kunci: Fleet, Forecast Rain Delay, Cost, Revenue, Coal Price, Discount Rate, Net Present Value

Flights Assignment Model of Multiple Airports Based on Game Theory and CDM Mechanism

To minimize delay cost of flights in multiple airports, this paper studied flights assignment problem under delay conditions. By considering the delay cost, airport capacity, and the slot exchange between airlines, this paper proposed a novel assignment model based on game theory and CDM mechanism. An improved ant colony algorithm was proposed to solve the flight assignment problem. The case studies showed that the proposed model can optimize the minimum delay cost between airlines under multiairport capacity constraints. The performance of proposed method was better than that of traditional non-slot-exchange method.

The Comparative Statics of Optimal Hierarchies

Several classes of models of hierarchical organizations share two common properties: the characteristics at different levels of the hierarchy are complementary, but this complementarity does not extend beyond adjacent levels. We propose a unified yet simple approach to study comparative statics of organizational characteristics with endogenous number of hierarchical layers in all these models. We use this new approach to study organizational decision making, and show that increased delay cost incentivizes the organization to empower lower level employees more than upper level employees. (JEL D21, D23, L23, M10)