Spatial Evolution Path of Historical International Community from the Perspective of Actor Network: A Case Study of Gulangyu Island

Gulangyu Island is a special case of social development and changes since modern China. In the past, Chinese and foreign people lived together and Chinese and Western cultures coexisted, resulting in an international community with outstanding cultural diversity and modern quality of life. As a functional carrier, space is of great reference significance to the research on the spatial evolution path of Gulangyu international community with the accelerating globalization and rapid expansion of urbanization. Based on the interpretation of historical maps and the integration of historical geographic information, this paper explores the evolution path of Gulangyu community space in modern times from the perspective of actor network theory. It is found that: (1) The change of key actors promotes the spatial evolution of Gulangyu international community. (2) In the stage of foreign culture dissemination (1840-1902), foreign nationals, as key actors, promoted the formation and development of actor networks through administrative recruitment and other means, and promoted Gulangyu Island to change from a traditional Minnan community to a modern community form, with the embryonic form of an international community beginning to emerge. (3) In the stage of multicultural integration (1903-1940), overseas Chinese returning home became key actors. The concept of combination of Western cultures was not only embodied in community management, but also acted on space practice to promote the multicultural integration of Gulangyu international community. This paper summarizes the effects of various factors on the evolution of community space, in order to provide reference for other coastal cities to rationally develop islands and promote the multicultural integration of local communities.

An Overview of Narrowband Internet of Things (NB-IoT) in the Modern Era

NB-IoT is the most suitable mobile network technology for IoT applications that require exceptionally extensive coverage added with extremely low power consumption, since these applications will generally be characterized by low data rates and moderate reaction times, usually in a few seconds, enabling the creation and development of solutions aimed at smart cities and smart environments. The NB-IoT technology can be characterized as a cellular LPWAN technology operating in a downlink within a bandwidth of 180 kHz and a sub-carrier space of 15 kHz and in the uplink, in general with a single tone transmission ranging between 3.75 kHz or 15 kHz, using coverage enhancement techniques, with characteristics of battery life for more than a decade and with specific battery-saving features. The ease that technological solutions of internet of things (IoT) make available through applications connected through intelligent sensors in traffic lights and parking lots; city pollution sensors; meters for energy, water, and sewage in cities, among other possibilities make systems more efficient, considering NB-IoT connectivity in relation to the treatment of information collected by devices allowing applications to be developed to address market needs. Therefore, this chapter aims to provide an updated discussion on narrowband technologies in the context of the IoT, showing and approaching its success, with a concise bibliographic background, categorizing and synthesizing the technological potential.

Classical and Quantum Integrability: A Formulation That Admits Quantum Chaos

The concept of integrability of a quantum system is developed and studied. By formulating the concepts of quantum degree of freedom and quantum phase space, a realization of the dynamics is achieved. For a quantum system with a dynamical group G in one of its unitary irreducible representative carrier spaces, the quantum phase space is a finite topological space. It is isomorphic to a coset space G/R by means of the unitary exponential mapping, where R is the maximal stability subgroup of a fixed state in the carrier space. This approach has the distinct advantage of exhibiting consistency between classical and quantum integrability. The formalism will be illustrated by studying several quantum systems in detail after this development.

Lorentz Group Projector Technique for Decomposing Reducible Representations and Applications to High Spins

The momentum-independent Casimir operators of the homogeneous spin-Lorentz group are employed in the construction of covariant projector operators, which can decompose anyone of its reducible finite-dimensional representation spaces into irreducible components. One of the benefits from such operators is that any one of the finite-dimensional carrier spaces of the Lorentz group representations can be equipped with Lorentz vector indices because any such space can be embedded in a Lorentz tensor of a properly-designed rank and then be unambiguously found by a projector. In particular, all the carrier spaces of the single-spin-valued Lorentz group representations, which so far have been described as 2 ( 2 j + 1 ) column vectors, can now be described in terms of Lorentz tensors for bosons or Lorentz tensors with the Dirac spinor component, for fermions. This approach facilitates the construct of covariant interactions of high spins with external fields in so far as they can be obtained by simple contractions of the relevant S O ( 1 , 3 ) indices. Examples of Lorentz group projector operators for spins varying from 1 / 2 –2 and belonging to distinct product spaces are explicitly worked out. The decomposition of multiple-spin-valued product spaces into irreducible sectors suggests that not only the highest spin, but all the spins contained in an irreducible carrier space could correspond to physical degrees of freedom.

Massless Rarita–Schwinger field from a divergenceless antisymmetric tensor-spinor of pure spin-3/2

We construct the Rarita–Schwinger basis vectors, [Formula: see text], spanning the direct product space, [Formula: see text], of a massless four-vector, [Formula: see text], with massless Majorana spinors, [Formula: see text], together with the associated field-strength tensor, [Formula: see text]. The [Formula: see text] space is reducible and contains one massless subspace of a pure spin-[Formula: see text]. We show how to single out the latter in a unique way by acting on [Formula: see text] with an earlier derived momentum independent projector, [Formula: see text], properly constructed from one of the Casimir operators of the algebra [Formula: see text] of the homogeneous Lorentz group. In this way, it becomes possible to describe the irreducible massless [Formula: see text] carrier space by means of the antisymmetric tensor of second rank with Majorana spinor components, defined as [Formula: see text]. The conclusion is that the [Formula: see text] bi-vector spinor field can play the same role with respect to a [Formula: see text] gauge field as the bi-vector, [Formula: see text], associated with the electromagnetic field-strength tensor, [Formula: see text], plays for the Maxwell gauge field, [Formula: see text]. Correspondingly, we find the free electromagnetic field equation, [Formula: see text], is paralleled by the free massless Rarita–Schwinger field equation, [Formula: see text], supplemented by the additional condition, [Formula: see text], a constraint that invokes the Majorana sector.

Nonstandard Dirac equations for nonstandard spinors

Generalized Dirac equation with operator mass term is presented. Its solutions are nonstandard spinors (NSS) which, like eigenspinoren des Ladungskonjugationsoperators (ELKO), are eigenvectors of the charge conjugation and dual-helicity operators. It is demonstrated that in spite of their noncovariant nature the NSS can serve as a carrier space of a representation of Poincaré group. However, the corresponding boost generators are not manifestly covariant and generate nonlocal momentum dependent transformations, which are presented explicitly. These results can present a new look on group-theoretical grounds of ELKO theories.