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We study vector-valued almost minimizers of the energy functional $$\int_D\left(|\nabla\mathbf{u}|^2+\frac2{1+q}\left(\lambda_+(x)|\mathbf{u}^+|^{q+1}+\lambda_-(x)|\mathbf{u}^-|^{q+1}\right)\right)dx,\quad00$, we take the epiperimetric inequality approach and prove the regularity for both almost minimizers and the set of "regular" free boundary points., Comment: 39 pages. arXiv admin note: text overlap with arXiv:2112.00676

We report the one-pot synthesis of 4-amino thiochromans using simple aminocyclopropanes and thiophenols through a formal [3+3] annulation reaction. This reaction proceeds under mild conditions with good functional group tolerance. The thiochroman core was formed with complete regioselectivity, and modification of complex drug molecules containing an aminocyclopropane was also realized.

It has become a popular research topic how data on Internet queries are used to make reliable predictions about changes in the marketplace. In this study we analyze the relationship between the online search volume of IPO or initial public offering stocks and their post-IPO stock returns. We obtain the online search data sets of the NAVER, one of the largest online search services in Korea, and the information on IPO stocks and their post-IPO stock returns at the Korea Exchange. We investigate the daily online search volume data of 87 companies that went public in the year of 2016. After analyzing the relations of the abnormal returns and online search volumes using the event study methods, we find that the lower the amount of online search for stocks before IPO, the higher the stock returns after IPO both in short and long-term. One standard deviation increase in search volume decreases one-day return by 3 basis points, two-day return by 6 basis points, and 4-day return by 10 basis points. These economically significant results become stronger if we control for benchmark returns, firm size, and book-to-market ratio. This finding suggests that IPO stocks with low investors’ attention based on the Internet search volume may be undervalued.

Background and purpose: Pyogenic spinal infection (PSI) has recently been on the rise due to aging and increasing degenerative spinal disease related procedures. PSI requires long-term antibiotic treatment and is followed by sustained functional disability even after successful treatment. This study aimed to analyze the clinical factors associated with medical burden and functional status of PSI. Methods: This retrospective study involved patients with non-postoperative PSI of thoraco-lumbo-sacral area in a single tertiary hospital. The length/cost of hospitalization with an antibiotic therapy and severity of back pain using the short form 36 (SF-36) were defined as the medical burden and functional status, respectively. We analyzed the clinical factors associated with medical burden and functional status. Results: We enrolled 142 patients (91 males and 51 females). The length and cost of hospitalization were 55.56 ± 27.09 (7–172) days and $14,070.17 ± 9289.39 (1611.87–48,722.35), respectively. A recurrence rate of 7.7% (11/142) and significant improvement of SF-36 at six months after completion of antibiotic treatment were noted (p < 0.05). Procedure-related (OR 2.702), C-reactive protein (CRP; OR 1.062), bacteremia (OR 4.966), additional surgical treatment (OR 6.524), recurrence (OR 12.453), and paraspinal abscess (OR 5.965) for above-average length of hospitalization were observed; female (OR 4.438), CRP (OR 1.071), bacteremia (OR 4.647), additional surgical treatment (OR 6.737), recurrence (OR 22.543), and extent of lesion (OR 1.431) for above-average cost of hospitalization; leg weakness (OR 15.966), white blood cell (WBC; OR 1.116), Charlson’s comorbidity index (CCI, OR 1.485), and identification of causative bacteria (OR 2.913) for below-average initial SF-36 were observed; leg weakness (OR 7.975) and WBC (OR 1.094) for below-average 6-month SF-36 were the statistically significant clinical factors in the multivariable logistic regression analysis (p < 0.05). Conclusion: Recurrence and leg weakness were identified as the most important clinical factors for medical burden and functional status in PSI, respectively. We think that it is necessary to actively suppress recurrence and manage neurological deficits for decreasing medical burden and achieving favorable functional outcome in the treatment of PSI.

In this paper we study vector-valued almost minimizers of the energy functional $$ \int_D\left(|\nabla\mathbf{u}|^2+2|\mathbf{u}|\right)\,dx . $$ We establish the regularity for both minimizers and the "regular" part of the free boundary. The analysis of the free boundary is based on Weiss-type monotonicity formula and the epiperimetric inequality for the energy minimizers., 25 pages

The Internet enables businesses to acquire a great deal of information, including prices in the open markets. In this study, we investigate what the value of reference price information is to a company in the market and how the company can make use of such information. Using business analytics, we were able to estimate prices of used cars for a rent-a-car company. The results show that a smart pricing information system is useful for collecting online reference price information and for estimating future prices of used cars and rental prices.

As game industry prospers, the negative side of games becomes highlighted as well as its contributions to economy growth. In spite of strong arguments for the necessity to regulations as a means to decrease addiction or overindulgence, research has produced future suggestions rather than quantifiable evidence. In this paper, we propose adopting a simulation approach in addition to quantitative approaches to better understand optimal regulatory levels since a simulation approach can visualize unexpected side effects of regulations. In this study, we suggest the application of an agent-based model (ABM) as a smart service to measure the effects of regulatory policies. We review cases applying ABM in various domains and consider the possibility of using an ABM to understand the effectiveness of web board-game regulations. We find that the ABM approach would be useful in several areas, such as the analysis of regulatory effects that reflect a variety of characteristics, the measurement of micro-regulatory effects, and the simulation of regulations.

We describe different modes of dimerization of various α',γ-dioxyenone derivatives with potential applications to the synthesis of high-order securinega alkaloids. We learned that the relative stereochemical relationship between α'- and γ-hydroxyl groups of the α',γ-dihydroxyenone derivative determines the mode of dimerization. While cis-α',γ-dioxyenone 26 provided the Rauhut-Currier-type (RC-type) dimer 31 upon reaction with TBAF, trans-α',γ-dihydroxyenone 34 afforded dimeric tetrahydrofuran derivative 41 under the same reaction conditions. We also noticed that the protection of the γ-hydroxyl group drastically changes the reaction outcomes. While cis-α'-oxy-γ-OPiv-enone 49 did not show any reactivity in the presence of TBAF, trans-α'-hydroxy-γ-OPiv-enone 45 produced the RC-type dimer 46 under the same reaction conditions. Computational analysis revealed the detailed mechanism of the latter transformation.

With the rapid increase in Groupon-like online daily deals, the behavior of consumers within online group buying has become a popular research topic. In addition, the increase of smart phone group buying has led merchants to consider increasing numbers of visitors beyond local consumers. The effects of the period, price, discount rate, and product category on sales are examined in the context of local consumers and visitors purchasing restaurant coupons in the group-buying electronic marketplace. Using linear and non-linear regressions and conjoint analysis as method, the actual transactional data sets of Dianping.com—one of Asia’s largest online group-buying businesses—is studied. The results show that there is a clear discrepancy between the preferences of the two consumer groups. Local consumers tend to think highly of discounts, while visitors are likely to care more about the product category. In addition, the behavior of the two groups differs in terms of product attribute selections. The findings could be useful to businesses in terms of understanding consumers’ purchasing and product designs.

In this paper, we empirically examine the ID fraud problem in online game. We analyzed over 260,000 users’ behavior using terabytes of big data. The results of the econometrics analysis showed that the behavior pattern of group around 40 years old was very similar to that of teenagers. Considering that the game used for the analysis is a game for young users, this means that some of the users in the group around 40 years old may be teenagers who have stolen the parent’s ID. In addition, we performed discriminant analysis and log traffic analysis to estimate how many young users were using their parent IDs. As a result, about 47% of the users around 40 years old were found to be teenager users. Also, behavior patterns of users who are estimated to be teenagers have been found in other age groups.

Do larger cities still suffer from higher crime rates? The scaling relationship between the number of crimes and the population size for the maximum of 758 cities with more than 50,000 inhabitants in the United States from 1999 to 2014 was analyzed. For the total group of cities, the relationship is superlinear for both violent and property crimes. However, for the subgroups of the top 12, top 24, and top 50 largest cities, the relationship changes to sublinear for both violent and property crimes. Results from the panel data analysis are in support of these findings. Along with population size, income per capita and population density also influence the outcome of crime counts. Implications from these findings will be discussed.

We consider Anzellotti-type almost minimizers for the thin obstacle (or Signorini) problem with zero thin obstacle and establish their $$C^{1,\beta }$$ regularity on the either side of the thin manifold, the optimal growth away from the free boundary, the $$C^{1,\gamma }$$ regularity of the regular part of the free boundary, as well as a structural theorem for the singular set. The analysis of the free boundary is based on a successful adaptation of energy methods such as a one-parameter family of Weiss-type monotonicity formulas, Almgren-type frequency formula, and the epiperimetric and logarithmic epiperimetric inequalities for the solutions of the thin obstacle problem.

Analyzing empirically the effects of the popularity information on sales.Presenting the results from controlled field experiments in an online store on Tmall.Identifying causality using difference-in-differences and propensity score matching.Presenting the hit list effects varying over subgroups of price and category. Popularity information is identified as one of the important factors for businesses in the online marketplace and is normally expected to strengthen sales performance. At the same time, the effects of popularity information are found to vary across product types. In this study, we attempt to identify the effects of popularity information on product sales through an analysis of the subgroups of category and price. Two sequential field experiments in an online apparel store on Alibaba's Tmall, the most dominant online brand marketplace in China, are conducted to capture the causal effects of the popularity information on sales. After observing the possible existence of popularity information effects through a pilot test of 17 products, we conduct the main experiment with 290 products, recording the daily sales for each by posting selected products on the hit list. The difference-in-differences method and propensity score matching are used to analyze the effects. The results show that once the products are displayed on the hit list, product sales increase by an average of 1.3units per day. One subgroup of the niche product category is found to be influenced more significantly by hit list information than are other subgroups in the broad appeal category. Furthermore, after the hit list information is presented, more units of mid-price products are likely to be sold than units of products with high and low prices.

Do larger cities still suffer from a higher crime rates? The scaling relationship between the number of crime counts and the population size for the maximum of 758 cities with more than 50,000 inhabitants in the United States during 1999 to 2014 was analyzed. For the total group of cities, the relation is superlinear for both violent and property crime. However, for the subgroups of top 12, top 24, and top 50 largest cities, the relations change to sublinear for both violent and property crime. Results from multivariate panel data analysis are in support of these findings. Next to population size, income per capita and population density have also influenced the outcome of crime counts. Implications from these findings will be discussed.

In 2008, a Korean online fashion distributor, Accommate, is founded in China and it tapped into the Chinese online market with the alliance of Taobao, online C2C(consumer-to-consumer) commerce platform of Alibaba. Taobao offered free listings to attract more sellers in order to compete e-bay and introduced keyword search features which Accommate made use of as an early adopter and partner. As Taobao became China’s market leader, Accommate secured the partner position to distribute Korean apparels and strengthened its partnership with Alibaba. Soon Alibaba introduced a new online brand mall called Taobao Mall or Tmall to complement the C2C platform. Accommate extended its business with Alibaba by taking charge of the Korean product sections in the online brand mall of Tmall. From the perspective of scales, China represented for Accommate a dynamic and fast-growing market, though it is so competitive. Moreover, it is a tough job

Projections of long-term carbon dioxide (CO2) emissions in the literature vary over a wide range depending on both socio-economic development and mitigation policy. Therefore, any attempt to improve the accuracy of such projections is important. We present a simple aggregate model to project the future carbon intensity of economic output, which is then used to forecast energy-related CO2 emissions through 2040 for seven countries and three regions of the world. Our projection results are compared to those from the International Energy Outlook 2013 report. We find that our projections are significantly higher than those reported in the International Energy Outlook 2013 report.

전자상거래 시장에서 롱테일 경제가 출현함에 따라 80/20 룰로 알려진 파레토 법칙의 일반적인 적용에 의문이 제기되고 있다. 이러한 제품 집중도의 변화는 인터넷 인프라 기반기술 위에 구현된 대량맞춤(mass customization)에서 기인한다고 예측된다. 본 연구는 그루폰과 유사한 소셜 커머스 웹사이트로부터 얻은 실거래 정보를 실증 분석하여 제품 및 고객 집중도를 분석하였다. 분석 결과, 이전 전자상거래 연구와 같이 소셜 커머스에서도 파레토 법칙과 다른 롱테일 패턴이 나타났다. 더욱이 email 또는 SMS를 통한 홍보가 판매 집중도 패턴에 영향을 미치는 것으로 파악되었다. email과 SMS를 통한 홍보는 모두 소셜 커머스 쿠폰 판매를 증가시킬 것이라는 예상과는 달리, SMS 홍보는 쿠폰 전반적으로 판매를 증가시키나, 소량판매 제품의 경우 email 홍보는 오히려 제품 판매를 감소시키는 결과를 보였다.

TicketMonster is a deal-of-the-day coupon site which utilizes the Internet and mobile infrastructure to offer deals in Seoul and other cities around Korea on services at restaurants, cafes, spas, and so forth. Following the company's rapid expansion, management made the decision to expand the scope of TicketMonster beyond Korea's borders with the aim of taking on other Asian markets. To this end, TicketMonster acquired Everyday.com.my, the biggest social shopping site in Malaysia. However, it was believed that simply competing in markets across Asia would not enable TicketMonster to claim sufficient market share in light of the international expansion of Groupon and LivingSocial, two online daily deal global giants. Furthermore, competition in the online daily deal sector in Korea had escalated as local, regional and international players vied for consumer awareness and loyalty. On top of an advertising war, competition grew to the point where several sites began selling coupons while knowingly taking a loss by lowering commissions in order to attract competitive products or services for their respective deals and at times paying for the services themselves. In mid-2011, U.S.-based LivingSocial made an offer to buy TicketMonster in order to strengthen its presence in Asia. Considering these changes and challenges, what are the strategic issues regarding TicketMonster and how should the company deal with the offer to deploy its transfer of ownership to LivingSocial? This case will help readers form an opinion on the related management issues and analyses.