Facebook used as an active marketing channel to expand customer base at a restaurant

The selected restaurant provides Cantonese style Chinese food. However, there has been a significant decrease in customers after opening day. The owner spent on newspaper promotion before opening day. The reality is that only a few people came. Therefore, the owner is looking for advice on the way of increasing his customer base and awareness. The project aims to demonstrate the value of using Facebook as a marketing channel to help a new Chinese restaurant promote itself to the public to increase profit and its customer base. The project gathered a total of 93 questionnaires and one interview by using mixed methods (quantitative and qualitative), followed by a theoretical review to show the owner that Facebook is the most effective channel to increase customer base and awareness. The results show that more than 95% of participants have social media and almost 92% of them have Facebook. 80% of participants agree that the restaurant should have a Facebook account so they can receive promotion and news. In conclusion, Facebook is the most effective and efficient channel to help the business get more attention from the public under the situation

Risk Limiting Dispatch with Ramping Constraints

Reliable operation in power systems is becoming more difficult as the penetration of random renewable resources increases. In particular, operators face the risk of not scheduling enough traditional generators in the times when renewable energies becomes lower than expected. In this paper we study the optimal trade-off between system and risk, and the cost of scheduling reserve generators. We explicitly model the ramping constraints on the generators. We model the problem as a multi-period stochastic control problem, and we show the structure of the optimal dispatch. We then show how to efficiently compute the dispatch using two methods: i) solving a surrogate chance constrained program, ii) a MPC-type look ahead controller. Using real world data, we show the chance constrained dispatch outperforms the MPC controller and is also robust to changes in the probability distribution of the renewables.Comment: Shorter version submitted to smartgrid comm 201

Retrospective Reader for Machine Reading Comprehension

Machine reading comprehension (MRC) is an AI challenge that requires machine to determine the correct answers to questions based on a given passage. MRC systems must not only answer question when necessary but also distinguish when no answer is available according to the given passage and then tactfully abstain from answering. When unanswerable questions are involved in the MRC task, an essential verification module called verifier is especially required in addition to the encoder, though the latest practice on MRC modeling still most benefits from adopting well pre-trained language models as the encoder block by only focusing on the "reading". This paper devotes itself to exploring better verifier design for the MRC task with unanswerable questions. Inspired by how humans solve reading comprehension questions, we proposed a retrospective reader (Retro-Reader) that integrates two stages of reading and verification strategies: 1) sketchy reading that briefly investigates the overall interactions of passage and question, and yield an initial judgment; 2) intensive reading that verifies the answer and gives the final prediction. The proposed reader is evaluated on two benchmark MRC challenge datasets SQuAD2.0 and NewsQA, achieving new state-of-the-art results. Significance tests show that our model is significantly better than the strong ELECTRA and ALBERT baselines. A series of analysis is also conducted to interpret the effectiveness of the proposed reader.Comment: Accepted by AAAI 202

Sorting Models in Discrete Choice Fisheries Analysis

One of the greatest challenges facing empirical fisheries researchers is to endogenize fishing effort in bioeconomic models in a way that accounts for fleet heterogeneity. Such heterogeneity can manifest in a wide range of both observable and unobservable characteristics of fishing vessels and individual fishermen. Without accounting for heterogeneity, we simply have an incomplete understanding of how pressure on fish resources responds to policy instruments that are available, the states of fish stocks, and exogenous shocks to the system. Largely due to data limitations, the discrete choice fisheries literature has focused on modeling unobserved heterogeneity through random parameters. In this paper, we draw on the industrial organization literature on product differentiation and the public economics literature on spatial sorting to estimate sorting models of observable heterogeneity. Models of this type estimate individual-specific structural coefficients based on observable individual characteristics and choice-specific constants using contraction mapping. We apply the methods to location choices and target species choices in the Gulf of Mexico reef-fish fishery. For this application, we have an unusual data set that couples daily observations from logbooks with demographic information from a mail survey of captains. We use contraction mapping to control for spatially-, and species-explicit stock information. The models are used to explore spatial and inter-temporal species effort substitution in response to two marine reserves, which are implemented in sample.Resource /Energy Economics and Policy,

X-ray Scattered Halo around IGR J17544-2619

X-ray photons coming from an X-ray point source not only arrive at the detector directly, but also can be strongly forward-scattered by the interstellar dust along the line of sight (LOS), leading to a detectable diffuse halo around the X-ray point source. The geometry of small angle X-ray scattering is straightforward, namely, the scattered photons travel longer paths and thus arrive later than the unscattered ones; thus the delay time of X-ray scattered halo photons can reveal information of the distances of the interstellar dust and the point source. Here we present a study of the X-ray scattered around IGR J17544-2619, which is one of the so-called supergiant fast X-ray transients. IGR J17544-2619 underwent a striking outburst when observed with Chandra on 2004 July 3, providing a near delta-function lightcurve. We find that the X-ray scattered halo around IGR J17544-2619 is produced by two interstellar dust clouds along the LOS. The one which is closer to the observer gives the X-ray scattered at larger observational angles; whereas the farther one, which is in the vicinity of the point source, explains the halo with a smaller angular size. By comparing the observational angle of the scattered halo photons with that predicted by different dust grain models, we are able to determine the normalized dust distance. With the delay times of the scattered halo photons, we can determine the point source distance, given a dust grain model. Alternatively we can discriminate between the dust grain models, given the point source distance.Comment: Accepted for publication in ApJ. 25 pages, 9 figures, 6 table