TEA-PSE 3.0: Tencent-Ethereal-Audio-Lab Personalized Speech Enhancement System For ICASSP 2023 DNS Challenge

This paper introduces the Unbeatable Team's submission to the ICASSP 2023 Deep Noise Suppression (DNS) Challenge. We expand our previous work, TEA-PSE, to its upgraded version -- TEA-PSE 3.0. Specifically, TEA-PSE 3.0 incorporates a residual LSTM after squeezed temporal convolution network (S-TCN) to enhance sequence modeling capabilities. Additionally, the local-global representation (LGR) structure is introduced to boost speaker information extraction, and multi-STFT resolution loss is used to effectively capture the time-frequency characteristics of the speech signals. Moreover, retraining methods are employed based on the freeze training strategy to fine-tune the system. According to the official results, TEA-PSE 3.0 ranks 1st in both ICASSP 2023 DNS-Challenge track 1 and track 2.Comment: Accepted by ICASSP 202

Fulfillment competition in availability and lead time

We examine the service competition in a product replenishment system and in a service delivery system. To excel the competitors in the competition, a supplier needs to understand the impact of her decision on the market share, and make the best decision considering the possible actions and reactions of the competitors. In a product replenishment system with multiple suppliers, customer reaction to a stockout is either accepting the delayed delivery (backorder, usually with some incentive) or taking the order elsewhere (lost sales). When customers take the sec-ond action, the suppliers suffer not only a loss of sales but also a loss of goodwill. In this thesis, we present two availability competition models for this problem: (1) dynamic competition model, and (2) attraction model. In the dynamic model, we consider the problem with two suppliers in a multi-period setting, and assume that a proportion of unsatisfied customers will switch supplier in the next period. We show the existence and uniqueness of Nash equilibrium, and prove that the dynamic game will converge to a stationary game. In the attraction model, we consider the problem with multiple suppliers in the long run. We assume that the fill rate is a key dimension of the product. We show the existence, uniqueness of Nash equilibrium, and discuss how the firm behavior is affected by the competi-tion. In a service delivery system, the supplier needs to quote a uniform delivery time for customers, while the quality of service, measured by the probability of on time delivery, must meet the market requirement. Both the lead time quotation and the service quality affect the attraction of the supplier, and hence the supplier needs to make suitable time decision to balance these two dimensions. We derive the optimal decision for the suppliers and provide some managerial insights. In particular, we show that whether a supplier should adopt an endogenous or ex-ogenous service quality, or whether she should make the decision based on her own parameters or based on the market requirement, depends on the capacities of the competing suppliers

Implications of Price Matching in Supply Chain Negotiation

Problem definition: Few papers have explored the impact of price matching negotiation (PM), in which a channel matches its price with the resulting wholesale price bargained by another channel, on firms’ performances, consumer welfare, and social welfare, with and without supply chain coordination. Academic/practical relevance: Negotiation has been widely seen in determining both uniform and discriminatory wholesale prices, which affect outcomes of competitive supply chain practices. Methodology: To characterize the PM mechanism, we use game theory and Nash bargaining theory to compare PM with simultaneous negotiation (SN) through a common-seller two-buyer differentiated Bertrand competition model. Results: Our analysis reveals that PM can benefit the seller but hurt all buyers, which is at odds with some fair wholesale pricing clauses intending to protect buyers. Under coordination with side payments, however, all firms can conditionally benefit more from PM than from SN. Despite firms’ gains, PM leads to less consumer utility and social welfare compared with SN, unless the second buyer in PM is considerably less powerful than the first buyer. Coordination further worsens PM’s negative impact on consumer utility and social welfare. Moreover, the existence of a spot market can increase the wholesale price in PM, hurting buyers, consumers, and society. Furthermore, the qualitative results about PM remain robust under an alternative disagreement point for PM, multiple buyers, and other extensions. Managerial implications: This paper delivers insights on when price matching in supply chain wholesale price negotiation can benefit a seller, buyers, consumers, and society in a variety of scenarios. It advocates how managers can use PM to their own advantages and provides rationale to decision makers for policy regulations regarding wholesale pricing

Promised Delivery Time and Capacity Games in Time-Based Competition

We investigate firms' competitive behaviors in industries where customers are sensitive to both promised delivery time (PDT) and quality of service (QoS) measured by the on-time delivery rate. To study the competition in PDT at the marketing level, we construct an oligopoly game with an external QoS requirement. We show that there exists a unique Nash equilibrium, and the equilibrium QoS exhibits a switching surface structure with respect to capacities. To study the competition in capacity at the strategic level, we construct a two-stage game in which the firms compete in terms of their capacities in stage 1 and in terms of PDT in stage 2. We show the existence of two different types of pure strategy equilibria and characterize them. This study provides the following insights: an index of time-based competitive advantage (ITCA) and the first-mover advantage determine the positions of the firms in time-based competition; either the well-known prisoner's dilemma or off-equilibrium behaviors due to different preferences for equilibria (when multiple equilibria exist) may lead the firms to overinvest in capacity, but no one may gain a competitive advantage; a uniform improvement in internal efficiency (i.e., a uniform capacity cost reduction) may harm everyone; quality differentiation (i.e., going beyond the QoS benchmark) plays a dual role in time-based competition, either helping a firm with a larger ITCA to compete more effectively, or helping a firm possibly with a smaller ITCA to preempt competitors and protect its market advantage. This paper was accepted by Paul H. Zipkin, operations and supply chain management.time-based competition, consumer choice model, Nash equilibrium, switching surface, quality differentiation, capacity competition, marketing-operations interface

Study of a passenger-taxi queueing system with nonzero matching time

In this paper, we study a passenger-taxi queueing systems in which nonzero matching time is considered. We assume that passengers and taxi drivers who arrive at a taxi station independently form two queues, and the waiting space for taxis is limited. We use a two-dimensional Markov process to model the system. By using matrix-analytic method, we give a sufficient condition that ensures the existence of steady-state probabilities and present an algorithm to calculate the joint steady-state probabilities. Further, we consider the tail distributions of sojourn times of passengers and taxi drivers, which can be computed by algorithms we present in this paper. And by running Matlab programs, we give the numerical results about the performance measures of the system

Dynamic competitive newsvendors with service-sensitive demands

When two firms compete for service-sensitive demands based on their product availability, their actions will affect the future market share reallocation. This problem was first studied by Hall and Porteus (2000) using a dynamic game model. We extend their work by incorporating a general demand model, which enables us to obtain properties that reveal the dynamics of the game and the behavior of the players. In particular, we provide conditions under which the market share of a firm has a positive value and give it an upper bound. We further extend the game competition model to an infinite-horizon setting. We prove that there exists a stationary equilibrium policy and that the dynamic equilibrium policy always converges to a stationary equilibrium policy. We demonstrate that demand patterns will dictate how firms compete rationally and show the likely outcomes of the competition