Evaluating Density Forecasts

We propose methods for evaluating density forecasts. We focus primarily on methods that are applicable regardless of the particular user's loss function. We illustrate the methods with a detailed simulation example, and then we present an application to density forecasting of daily stock market returns. We discuss extensions for improving suboptimal density forecasts, multi-step-ahead density forecast evaluation, multivariate density forecast evaluation, monitoring for structural change and its relationship to density forecasting, and density forecast evaluation with known loss function.

Evaluating density forecasts

The authors propose methods for evaluating and improving density forecasts. They focus primarily on methods that are applicable regardless of the particular user's loss function, though they take explicit account of the relationships between density forecasts, action choices, and the corresponding expected loss throughout. They illustrate the methods with a detailed series of examples, and they discuss extensions to improving and combining suboptimal density forecasts, multistep-ahead density forecast evaluation, multivariate density forecast evaluation, monitoring for structural change and its relationship to density forecasting, and density forecast evaluation with known loss function.Forecasting

Some Notes on the Malayan Law of Negligence

In the annals of the spread of the common law to other lands and other ways, Malaya may deserve a modest place, but, as the selection here no doubt shows, so far it has made no significant contribution to the intellectual content of that law. It has neither produced nor harboured a Cardozo or a Dixon. At best, its judges have applied common law principles simply but soundly; they have never, at least in tort, been subtle or illuminating. Its legal history is of interest for its own sake; its legal achievement awaits us in the future, not in the past

Real-Time Cure Monitoring of Unsaturated Polyester Resin from Ultra-Violet Curing

Real time Fourier transform infrared (RTFT-IR) spectroscopy reveals the influence of the nature of the photoinitiator on the kinetics for the polymerization reaction. Real time cure monitoring was used to determine the polymerization rate of ultra-violet cured unsaturated polyester resins (UPR1:2-1:5) based on palm oil and containing styrene as a cross-linking agent in the presence of IRGACURE 184 photoinitiator. Firstly, variable types of UPR1:2-1:5 were prepared using various ratios of monoglyceride (MG) monomer to maleic anhydride which used as a source of double bond using polycondensation technique. RTFT-IR spectroscopy was used to characterize the ultra-violet curing kinetics for all the systems. This technique offered a powerful approach for monitoring changes in the chemical properties of the system during the ultra-violet curing. Pseudo first order kinetics for all UPR1:2-1:5 curable systems were determined and the rate constant values and regression coefficients were calculated. Furthermore, the thermal behaviour and morphological features for the photo-fabricated UPR1:2-1:5 systems were examined. The thermal analyses for the cured films were evaluated by TGA, DTG and DSC in nitrogen atmosphere at a heating rate of 10°C/min. All the formulations showed similar degradation pattern at 40 % and 50 % weight losses (Td = 40% and Td =50% respectively) except polymer UPR1:5 which had somewhat lower degree in the same range. In addition, the morphological properties for photo-fabricated UPR1:2,1:3,1:5 were investigated by using scanning electron microscopy.

Type-II Topological Dirac Semimetals: Theory and Materials Prediction (VAl3 family)

The discoveries of Dirac and Weyl semimetal states in spin-orbit compounds led to the realizations of elementary particle analogs in table-top experiments. In this paper, we propose the concept of a three-dimensional type-II Dirac fermion and identify a new topological semimetal state in the large family of transition-metal icosagenides, MA3 (M=V, Nb, Ta; A=Al, Ga, In). We show that the VAl3 family features a pair of strongly Lorentz-violating type-II Dirac nodes and that each Dirac node consists of four type-II Weyl nodes with chiral charge +/-1 via symmetry breaking. Furthermore, we predict the Landau level spectrum arising from the type-II Dirac fermions in VAl3 that is distinct from that of known Dirac semimetals. We also show a topological phase transition from a type-II Dirac semimetal to a quadratic Weyl semimetal or a topological crystalline insulator via crystalline distortions. The new type-II Dirac fermions, their novel magneto-transport response, the topological tunability and the large number of compounds make VAl3 an exciting platform to explore the wide-ranging topological phenomena associated with Lorentz-violating Dirac fermions in electrical and optical transport, spectroscopic and device-based experiments.Comment: 28 pages, 7 Figure

New fermions on the line in topological symmorphic metals

Topological metals and semimetals (TMs) have recently drawn significant interest. These materials give rise to condensed matter realizations of many important concepts in high-energy physics, leading to wide-ranging protected properties in transport and spectroscopic experiments. The most studied TMs, i.e., Weyl and Dirac semimetals, feature quasiparticles that are direct analogues of the textbook elementary particles. Moreover, the TMs known so far can be characterized based on the dimensionality of the band crossing. While Weyl and Dirac semimetals feature zero-dimensional points, the band crossing of nodal-line semimetals forms a one-dimensional closed loop. In this paper, we identify a TM which breaks the above paradigms. Firstly, the TM features triply-degenerate band crossing in a symmorphic lattice, hence realizing emergent fermionic quasiparticles not present in quantum field theory. Secondly, the band crossing is neither 0D nor 1D. Instead, it consists of two isolated triply-degenerate nodes interconnected by multi-segments of lines with two-fold degeneracy. We present materials candidates. We further show that triplydegenerate band crossings in symmorphic crystals give rise to a Landau level spectrum distinct from the known TMs, suggesting novel magneto-transport responses. Our results open the door for realizing new topological phenomena and fermions including transport anomalies and spectroscopic responses in metallic crystals with nontrivial topology beyond the Weyl/Dirac paradigm.Comment: 24 pages, 4 figures, and 1 tabl

Mechanical And Thermal Properties Of Hydroxyapatite Filled Poly(Methyl Methacrylate) Composites.

Poly(methyl methacrylate) (PMMA) filled with hydroxyapatite (HA) filler has been widely used in biomaterial application. Acrylic denture base material was prepared from PMMA filled with HA

Analisa Perkuatan Geotekstil Pada Timbunan Konstruksi Jalan Dengan Plaxis 2d

Permasalahan yang sering terjadi pada timbunan adalah terjadinya penurunan yang besar. Oleh karena itu diperlukan perkuatan untuk memperbaiki kondisi tersebut. Salah satu USAha perkuatan tanah yang dapat dilakukan adalah dengan memasang geotekstil. Tujuan penelitian ini untuk menganalisa kuat tarik geotekstil yang digunakan serta menentukan kuat tarik optimum geotekstil yang akan digunakan sebagai perkuatan dengan memperhatikan nilai angka keamanan dan penurunan. Penelitian ini menggunakan tiga pemodelan yaitu, yang pertama pengujian pada timbunan yang tidak menggunakan geotekstil. Pengujian kedua yaitu untuk menentukan panjang geotekstil yang akan digunakan. Pengujian ketiga, pengujian pada timbunan yang menggunakan geotekstil dengan kuat tarik yang bervariasi, dengan panjang yang ditentukan berdasarkan hasil pola keruntuhan yang terjadi pada pengujian kedua.Hasil dari penelitian ini menunjukkan bahwa dengan adanya penggunaan geotekstil, pola keruntuhan yang terjadi mengalami Perubahan, dimana bagian yang runtuh hanya pada timbunan saja.Penurunan yang terjadi pada timbunan dengan perkuatan geotekstil semakin kecil dan nilai angka keamanan yang diperoleh melebihi batas minimum nilai angka keamanan ijin