On the Number of Circuit-cocircuit Reversal Classes of an Oriented Matroid

The first author introduced the circuit-cocircuit reversal system of an oriented matroid, and showed that when the underlying matroid is regular, the cardinalities of such system and its variations are equal to special evaluations of the Tutte polynomial (e.g., the total number of circuit-cocircuit reversal classes equals $t(M;1,1)$, the number of bases of the matroid). By relating these classes to activity classes studied by the first author and Las Vergnas, we give an alternative proof of the above results and a proof of the converse statements that these equalities fail whenever the underlying matroid is not regular. Hence we extend the above results to an equivalence of matroidal properties, thereby giving a new characterization of regular matroids.Comment: 7 pages. v2: simplified proof, with new statements concerning other special evaluations of the Tutte polynomia

The dimension of an amoeba

Answering a question by Nisse and Sottile, we derive a formula for the dimension of the amoeba of an irreducible algebraic variety.Comment: 8 pages, several small improvements, final versio

From Your Preferences to Niche Tourism: A New “To-Do” List in Hong Kong

There are a lot of services and mobile applications that allow simplifying a search, proactively providing information about famous attractions and user feedback; but travelers may have difficulty in choosing based on their real needs. Smart tourism, under the rapid growth of Internet of Things and machine learning techniques is developed for enhancing travellers’ experience and satisfaction. In recent years, it is essential for most tourism industrialists to strengthen their competitive edge and to improve industrial sustainability through the adoption of smart tourism. In this chapter, the proposed model generates travel recommendations and related useful information to end users through an online platform, namely Niche-E-Travel (NET). This distinctive tourism solution aims to collect all the obscure attractions, to align them with visitors’ interests, and to provide them with a new to-do list in Hong Kong. NET collects basic information from end users and uses the proposed travel analytic model with K-modes and K-means clustering methods to finish a clustering process, and provide some potential activity plans to fit the end user’s interests and requirements. Recommendations made for each user are supported by collaborative filtering to compare different users’ personal interests

Treating of Rayon-flocked Fabric by Atmospheric Pressure Plasma

This study investigates hydrophobisation of the surface of rayon-flocked fabric by means of atmospheric pressure plasma (APP) treatment with tetramethylsilane (TMS). Plasma deposition of TMS is regarded as an effective, single-step low pollution method. A detailed study of the process parameters was conducted. A highly hydrophobic surface was successfully fabricated on rayon-flocked fabric and the hydrophobic surface was found to have good stain resistance to coffee and milk tea

The amoeba dimension of a linear space

Given a complex vector subspace $V$ of $\mathbb{C}^n$, the dimension of the amoeba of $V \cap (\mathbb{C}^*)^n$ depends only on the matroid of $V$. Here we prove that this dimension is given by the minimum of a certain function over all partitions $P_1, \dots, P_k$ of the ground set into nonempty parts $P_i$, as previously conjectured by Rau. We also prove that this formula can be evaluated in polynomial time

STUDENT-CONTROLLED SOCIAL NETWORKS FOR PROMOTING HOLISTIC DEVELOPMENT FROM THE PRESPECTIVES OF STUDENT COACHES

Many previous research works have studied the impact of online social networks for educational purposes. We examine in particular how Facebook is being used as a platform to communicate among students of an on-going student development project run by a local tertiary institute in Hong Kong so as to facilitate promotion and foster participation and interaction. The study focuses on the perspectives from student coaches and evaluate on the facilitation and difficulties in promoting self-initiated holistic development via Facebook. The study shows that instant interaction between participants and student coaches via Facebook can lead to information circulation in a much faster and effective manner compared with traditional communication channels such as email or bulletins. However, limitations are found on the lack of proactive discussions initiated by participants, and the difficulties in establishing active interactions between coaches and participants. This has undermined the effectiveness of promoting to participants’ in self-initiated holistic development