Inevitability of the Poisson Bracket Structure of the Relativistic Constraints

The purpose of this paper is to shed some fresh light on the long-standing conceptual question of the origin of the well-known Poisson bracket structure of the constraints that govern the canonical dynamics of generally relativistic field theories, i.e. geometrodynamics. This structure has long been known to be the same for a wide class of fields that inhabit the space-time, namely those with non-differential coupling to gravity. It has also been noticed that an identical bracket structure can be derived independently of any dynamical theory, by purely geometrical considerations in Lorentzian geometry. Here we attempt to provide the missing link between the dynamics and geometry, which we understand to be the reason for this structure to be of the specific kind. We achieve this by a careful analysis of the geometrodynamical approach, which allows us to derive the structure in question and understand it as a consistency requirement for any such theory. In order to stay close to the classical literature on the subject we stick to the metric formulation of general relativity, but the reasoning should carry over to any other formulation as long as the non-metricity tensor vanishes. The discussion section is devoted to derive some interesting consequences of the presented result in the context of reconstructing the Arnowitt–Deser–Misner (ADM) framework, thus providing a precise sense to the inevitability of the Einstein’s theory under minimal assumptions.

Social Media Crisis Communication Model for Building Public Resilience: A Preliminary Study

There is an ongoing discussion about the effectiveness of social media usage on the ability of people to recover from the crisis. However, the existing social media crisis communication models could not address the dynamic feature of social media users and the crisis, respectively. Therefore, the objective of this study is to conduct a preliminary investigation of the social media crisis communication model for building public resilience. Thus, 34 items were generated from the literature concerning the crisis, crisis response, social interaction, and resilience. The items were validated by three experts via content validity index and modified kappa statistics. After passing the validation test, the instruments were pre-tested by 32 participants. The reliability of the items was analyzed using Cronbach’s alpha. Also, the model fits and mediation were examined by the regression model, and the hypotheses were independently assessed in process macro models. Based on the result obtained, each of the constructs satisfied the internal consistency requirement; crisis (0.743), crisis response (0.724), social media interaction (0.716), and resilience (0.827). Furthermore, the result also indicates that the regression model is a good fit for the data. The independent variables statistically significantly predict the dependent variable, p < 0.05. Also, the result of the process macro models indicates that all the hypotheses are independently supported.

Educating Students to Consistency via Argumentation

In this paper, the role played in learning to argue by an essential and yet under-researched epistemic and argumentative norm is discussed, namely, the consistency requirement. An argumentative intervention is presented, that is designed to enhance the understanding of this norm among high school students, to enable them to recognize contradictions in the process of argumentation and to familiarize them with the argumentative strategies related to the reductio ad absurdum. There follows a description of how the designed intervention was implemented in two Italian high schools, which served as an exploratory case study, and the results obtained are discussed.

$S$ -matrix unitarity and renormalizability in higher-derivative theories

We investigate the relation between $S$-matrix unitarity ($SS^\dagger=1$) and renormalizability in theories with negative-norm states. The relation has been confirmed in many field theories, including gauge theories and Einstein gravity, by analyzing the unitarity bound, which follows from the $S$-matrix unitarity and the norm positivity. On the other hand, renormalizable theories with a higher-derivative kinetic term do not necessarily satisfy the unitarity bound because of the negative-norm states. In these theories it is not known whether the $S$-matrix unitarity provides a nontrivial constraint related to the renormalizability. In this paper, by relaxing the assumption of norm positivity we derive a bound on scattering amplitudes weaker than the unitarity bound, which may be used as a consistency requirement for $S$-matrix unitarity. We demonstrate in scalar field models with a higher-derivative kinetic term that the weaker bound and the renormalizability imply identical constraints.

Mengukur Performa Enterprise Architecture Framework Menggunakan Fuzzy Tsukamoto

Enterprise Architecture (EA) adalah deskripsi dari misi stakeholder yang menggambarkan rencana pengembangan sebuah sistem atau sekumpulan sistem untuk mencapai sebuah misi organisasi melalui performansi optimal dari proses bisnis dalam sebuah lingkungan TI yang efisien. Untuk bisa menerapkan EA dalam sebuah organisasi, dibutuhkan kerangka kerja yang bersifat fundamental dan satu set alat pendukung yang digunakan untuk mengembangkan suatu EA. Pengukuran performa EA framework dirasa perlu, untuk mengetahui EA framework yang applicable pada kondisi saat ini. Sehingga dibutuhkan sebuah <em>decision support</em> untuk membantu memilih EA framework berdasarkan kriteria penilaian dari sisi artifact, governance, strategy, consistency, requirement, guidelines, dan continual. Pada makalah ini dibahas pembuatan decission support system untuk mengukur performa EA framework menggunakan Sistem Inferensi Fuzzy Tsukamoto. Parameter yang digunakan untuk batasan fungsi keanggotaan fuzzy berdasarkan data yang diperoleh dari pakar yaitu artifact, governance, strategy, consistency, requirement, guidelines, dan continual. Akurasi sistem dihitung berdasarkan hasil perbandingan dari keluaran sistem dengan hasil penilaian pakar.