Intra-metropolitan Office Price and Trading Volume Dynamics: Evidence from Hong Kong

Previous studies of the office market have tended to focus on either the rental market or the aggregate sales market. This paper focuses on the intra-metropolitan sales market and on office price and trading volume dynamics in Hong Kong. According to our findings, buildings trading at higher prices are not necessarily traded more often than those trading at lower prices. In addition, the price of offices in different categories does not necessarily move in tandem. The trading volumes of higher priced buildings tend to Granger cause the lower priced buildings, and this conclusion is robust to alternative classifications. The paper contrasts several existing theories. Suggestions for future research are also discussed.Commercial property; Correlation

On the Stability of the Implicit Prices of Housing Attributes: A Dynamic Theory and Some Evidence

Given the dramatic fluctuations in aggregate housing prices, this paper attempts to examine whether the implicit prices of different housing attributes are “stable.” Theoretically, this paper provides perhaps the first dynamic, general equilibrium model in which housing attributes’ implicit prices fluctuate. Empirically, this paper models the time paths of different implicit prices as auto-regressive processes by employing a hedonic pricing model on a large set of housing transaction data over a relatively long period of time. An endogenous structural break test is then performed. Except for a few attributes, structural breaks are not detected. Directions for future research are discussed.hedonic pricing; structural break; evolution of valuation; housing attributes

A Dynamic Programming Algorithm for Finding an Optimal Sequence of Informative Measurements

An informative measurement is the most efficient way to gain information about an unknown state. We present a first-principles derivation of a general-purpose dynamic programming algorithm that returns an optimal sequence of informative measurements by sequentially maximizing the entropy of possible measurement outcomes. This algorithm can be used by an autonomous agent or robot to decide where best to measure next, planning a path corresponding to an optimal sequence of informative measurements. The algorithm is applicable to states and controls that are either continuous or discrete, and agent dynamics that is either stochastic or deterministic; including Markov decision processes and Gaussian processes. Recent results from the fields of approximate dynamic programming and reinforcement learning, including on-line approximations such as rollout and Monte Carlo tree search, allow the measurement task to be solved in real time. The resulting solutions include non-myopic paths and measurement sequences that can generally outperform, sometimes substantially, commonly used greedy approaches. This is demonstrated for a global search task, where on-line planning for a sequence of local searches is found to reduce the number of measurements in the search by approximately half. A variant of the algorithm is derived for Gaussian processes for active sensing

從新歷史主義視角看黃帝大戰蚩尤 : 以神話、諸子學說及史家為例

黃帝與蚩尤的戰爭是中國古代規模較大的神話傳說。其始於戰國初年就有記載，至唐宋時代，其流傳演變不絕，是中國神話傳說影響最廣的。它基本反映了原始社會部落間的戰爭。從神話角度看，黃帝與蚩尤是天神；從傳說角度看，他們是兩大部落的首領。隨著時間的推移，黃帝與蚩尤的戰爭神話也因時勢而有所變改，更有和歷史雜糅的情況。 前人研究黃帝大戰蚩尤的主題有二：一，蚩尤的形象研究，如：吳家衡在〈「失敗戰神」——論蚩尤的戰神「專職化」和「神位條件」〉探討蚩尤形象二元對立的矛盾，衪是戰敗的一方，又是象徵邪惡的亂世叛臣，但卻被世人奉為民族的保護神。二，從互文性的角度分析不同作品中對黃帝大戰蚩尤的描寫，如：鄭巧賢、張仁軒於〈以《墉城集仙錄》為本看《太平廣記．西王母》中黃帝戰蚩尤的重現〉，就是以《墉城集仙錄》和《太平廣記．西王母》兩篇文本的對讀，分析當中黃帝與蚩尤形象，及兩部作品對大戰描寫的異同。 黃帝大戰蚩尤的神話雖然與歷史雜糅一起，又於戰國時代被諸子各家以其作學說的支持理據流傳，但就鮮有學者以此為主題作深入的探討。本文會從新歷史主義的角度出發，並以《山海經》、諸子各家學說及史家為例，察看黃帝大戰蚩尤的神話歷史化

Association between antibiotic consumption and colon and rectal cancer development in older individuals: A territory‐wide study

Background: Antibiotics may alter colorectal cancer (CRC) risk due to gut dysbiosis. We aimed to study the specific and temporal effects of various antibiotics on CRC development in older individuals. Methods: This was a territory-wide retrospective cohort study. Subjects aged 60 years and older who did not have CRC diagnosed on screening/diagnostic colonoscopy diagnosed between 2005 and 2013 were recruited. Exclusion criteria were history of CRC, colectomy, inflammatory bowel disease, and CRC diagnosed within 6 months of index colonoscopy. Exposure was use of any antibiotics up to 5 years before colonoscopy. The primary outcomes were CRC diagnosed >6 m after colonoscopy. Covariates were patient demographics, history of colonic polyps/polypectomy, concomitant medication use (NSAIDs, COX-2 inhibitors, aspirin, and statins), and performance of endoscopy centers (colonoscopy volume and polypectomy rate). Stratified analysis was conducted according to nature of antibiotics and location of cancer. Results: Ninety seven thousand one hundred and sixty-two eligible subjects (with 1026 [1.0%] cases of CRC) were identified, 58,704 (60.4%) of whom were exposed to antibiotics before index colonoscopy. Use of antibiotics was associated with a lower risk of cancer in rectum (adjusted hazard ratio [aHR]: 0.64, 95% CI: 0.54–0.76), but a higher risk of cancer in proximal colon (aHR: 1.63, 95%CI: 1.15–2.32). These effects differed as regards the anti-anaerobic/anti-aerobic activity, narrow-/broad-spectrum, and administration route of antibiotics. Conclusions: Antibiotics had divergent effects on CRC development in older subjects, which varied according to the location of cancer, antibiotic class, and administration route

Multiple Block-Size Search Algorithm for Fast Block Motion Estimation

Abstract-Although variable block-size motion estimation provides significant video quality and coding efficiency improvement, it requires much higher computational complexity compared with fixed block size motion estimation. The reason is that the current motion estimation algorithms are mainly designed for fixed block size. Current variable block-size motion estimation implementation simply applies these existing motion estimation algorithms independently for different block sizes to find the best block size and the corresponding motion vector. Substantial computation is wasted because distortion data reuse among motion searches of different block sizes is not considered. In this paper, a motion estimation algorithm intrinsically designed for variable block-size video coding is presented. The proposed multiple block-size search (MBSS) algorithm unifies the motion searches for different block sizes into a single searching process instead of independently performing the search for each block size. In this unified search, the suboptimal motion vectors for different block sizes are used to determine the next search steps. Its prediction quality is comparable with that obtained by performing motion search for different block sizes independently while the computational load is substantially reduced. Experimental results show that the prediction quality of MBSS is similar to full search. Block matching, motion estimation, video coding, search pattern, directional search