Exact and Approximate Methods for Machine Translation Decoding

Statistical methods have been the major force driving the advance of machine translation in recent years. Complex models are designed to improve translation performance, but the added complexity also makes decoding more challenging. In this thesis, we focus on designing exact and approximate algorithms for machine translation decoding. More specifically, we will discuss the decoding problems for phrase-based translation models and bidirectional word alignment. The techniques explored in this thesis are Lagrangian relaxation and local search. Lagrangian relaxation based algorithms give us exact methods that have formal guarantees while being efficient in practice. We study extensions to Lagrangian relaxation that improve the convergence rate on machine translation decoding problems. The extensions include a tightening technique that adds constraints incrementally, optimality-preserving pruning to manage the search space size and utilizing the bounding properties of Lagrangian relaxation to develop an exact beam search algorithm. In addition to having the potential to improve translation accuracy, exact decoding deepens our understanding of the model that we are using, since it separates model errors from optimization errors. This leads to the question of designing models that improve the translation quality. We design a syntactic phrase-based model that incorporates a dependency language model to evaluate the fluency level of the target language. By employing local search, an approximate method, to decode this richer model, we discuss the trade-off between the complexity of a model and the decoding efficiency with the model

Width-tuned magnetic order oscillation on zigzag edges of honeycomb nanoribbons

Quantum confinement and interference often generate exotic properties in nanostructures. One recent highlight is the experimental indication of a magnetic phase transition in zigzag-edged graphene nanoribbons at the critical ribbon width of about 7 nm [G. Z. Magda et al., Nature \textbf{514}, 608 (2014)]. Here we show theoretically that with further increase in the ribbon width, the magnetic correlation of the two edges can exhibit an intriguing oscillatory behavior between antiferromagnetic and ferromagnetic, driven by acquiring the positive coherence between the two edges to lower the free energy. The oscillation effect is readily tunable in applied magnetic fields. These novel properties suggest new experimental manifestation of the edge magnetic orders in graphene nanoribbons, and enhance the hopes of graphene-like spintronic nanodevices functioning at room temperature.Comment: 22 pages, 9 figure

ERP Post-Implementation Learning, ERP Usage And Individual Performance Impact

In recent years, an increasing number of companies that have implemented ERP systems have expressed disappointment over a failure to reach anticipated goals. A major reason for this failure is the inefficient use of the ERP system by employees. Therefore, the critical issue is how users can most effectively take advantage of an ERP system. Post-implementation learning plays an important role in facilitating ERP usage and thus promotes individual performance. Particularly, the integrated and sophistic natures of ERP systems force users to learn continuously after ERP implementation. This study employed a survey method to examine the perceptions of a dataset of 659 ERP users. We found that ERP usage facilitates individual performance, including individual productivity, customer satisfaction and management control, and post-implementation learning contributes to all three types of ERP usage, including decision support, work integration and customer service. Our findings can provide academics and practitioners with knowledge of how to improve ERP usage and ensure individual performance impacts

Sustainabilitas Arsitektur Masjid: Evaluasi Konsep “Simple Architecture” sebagai Implementasi Desain Arsitektur Berkelanjutan suatu Kawasan

Makalah ini membahas aspek-aspek “kesederhanaan” (simplicity) sebagai konsep desain bangunan masjid secara berkelanjutan (sustainable) sesuai konteks dengan mengambil studi kasus masjid kawasan Al-Irsyad Satya Kota Baru Parahyangan, Bandung. Masjid sebagai subyek arsitektur dan pusat ibadah menjadi ruang publik yang didesain dari elemen-elemen yang secara ideal mengandung nilai-nilai Islam dan bertujuan mendukung fungsinya. Desain masjid berkonsep simple atau “sederhana” digunakan sebagai alternatif kontemporer untuk mengoptimalisasi fungsi tersebut, meliputi struktur bangunan hingga biaya pemeliharaan (maintenance) sesuai prinsip keberlanjutan. Keterkaitan erat bangunan masjid dengan aktivitas masyarakat berpotensi melibatkan partisipasi masyarakat dan pengelola dalam menerapkan program sustainabilitas sesuai konteks lingkungannya. Metode yang digunakan dalam penelitian ini berbasis pendekatan Grounded Theory secara kualitatif melalui pengumpulan data dari kegiatan observasi, interview dan analisis program keberlanjutan kawasan. Penelitian menemukan keterkaitan konsep “sederhana” yang mendukung sustainabilitas desain sekaligus menggarisbawahi evaluasi konsep desain “sederhana” yang hadir serta faktor pemeliharaan/pengembangan masjid dan kawasan

Hydroxonium 1-ammonio­ethane-1,1-diyl­diphospho­nate

The title complex, H3O+·NH3C(CH3)(PO3H)2 −, contains a hydroxonium ion and an NH3C(CH3)(PO3H)2 − anion. The three H atoms of H3O+ form a pseudo-tetra­hedron by being distributed over four positions with occupation factors of 0.75. Multiple N—H⋯O and O—H⋯O hydrogen bonds in the crystal structure form an intricate three-dimensional supra­molecular network

Binding of PFOS to serum albumin and DNA: insight into the molecular toxicity of perfluorochemicals

<p>Abstract</p> <p>Background</p> <p>Health risk from exposure of perfluorochemicals (PFCs) to wildlife and human has been a subject of great interest for understanding their molecular mechanism of toxicity. Although much work has been done, the toxigenicity of PFCs remains largely unknown. In this work, the non-covalent interactions between perfluorooctane sulfonate (PFOS) and serum albumin (SA) and DNA were investigated under normal physiological conditions, aiming to elucidate the toxigenicity of PFCs.</p> <p>Results</p> <p>In equilibrium dialysis assay, the bindings of PFOS to SA correspond to the Langmuir isothermal model with two-step sequence model. The saturation binding number of PFOS was 45 per molecule of SA and 1 per three base-pairs of DNA, respectively. ITC results showed that all the interactions were spontaneous driven by entropy change. Static quenching of the fluorescence of SA was observed when interacting with PFOS, indicating PFOS bound Trp residue of SA. CD spectra of SA and DNA changed obviously in the presence of PFOS. At normal physiological conditions, 1.2 mmol/l PFOS reduces the binding ratio of Vitamin B₂to SA by more than 30%.</p> <p>Conclusion</p> <p>The ion bond, van der Waals force and hydrophobic interaction contributed to PFOS binding to peptide chain of SA and to the groove bases of DNA duplex. The non-covalent interactions of PFOS with SA and DNA alter their secondary conformations, with the physiological function of SA to transport Vitamin B₂being inhibited consequently. This work provides a useful experimental method for further studying the toxigenicity of PFCs.</p