Value Discount of Business Groups Surrounding the Asia Financial Crisis: Evidence from Korean Chaebols

Asian Financial Crisis, Business Group, Chaebol, Diversification, Firm Value

Contextual Linear Bandits under Noisy Features: Towards Bayesian Oracles

We study contextual linear bandit problems under uncertainty on features; they are noisy with missing entries. To address the challenges from the noise, we analyze Bayesian oracles given observed noisy features. Our Bayesian analysis finds that the optimal hypothesis can be far from the underlying realizability function, depending on noise characteristics, which is highly non-intuitive and does not occur for classical noiseless setups. This implies that classical approaches cannot guarantee a non-trivial regret bound. We thus propose an algorithm aiming at the Bayesian oracle from observed information under this model, achieving $\tilde{O}(d\sqrt{T})$ regret bound with respect to feature dimension $d$ and time horizon $T$. We demonstrate the proposed algorithm using synthetic and real-world datasets.Comment: 30 page

Immunoglobulin VH Chain Gene Analysis of Peripheral Blood IgM-Producing B Cells in Patients with Kawasaki Disease

PURPOSE: Kawasaki disease is a systemic vasculitis, and its etiology and pathogenesis are still not clear. Our study was undertaken to investigate the characteristics of the activation of B cells in the peripheral blood of Kawasaki disease (KD) patients and evidence of stimulation by superantigens. MATERIALS AND METHODS: Blood samples were obtained from three patients (2 males, 1 female) with KD, who were admitted to our Hospital, Seoul, Korea. The mean age was 1.2 years. Distribution of B cells was studied in the acute and subacute phases of KD patients. From the RNA of B cells, we obtained complementary DNA (cDNA) and performed polymerase chain reaction (PCR). To determine the oligoclonal expansion of immunoglobulin M (IgM) V(H) family, we cloned and sequenced the PCR products from each group and analyzed DNA. RESULTS: In the peripheral blood of acute phase patients, T cells were significantly decreased (p < 0.05), whereas B cells were significantly increased (p < 0.05). When the first PCR was done on the B cell chains, V(H)1 to V(H)6 were all found to be expressed. The number of micro gene clones obtained from 3 patients was 312, and they belonged to V(H)3, V(H)4 and V(H)5 family. M99686 germ line was most frequently used and the next most frequently used, were X92224/J, L21967 and L21964. A similar order was seen in patients. Among the clones, 20 sets of clones showed the same base sequence and this was frequent between V(H)2 and V(H)5. There was one set, which showed almost the same base sequence between different patients, and the homology was 99.5%. Twenty sets of clones that had the same base sequence showed high similarity to the germ line (94 - 100%). Among these, the clones that utilized the M99686 germ line were 4 sets which were most frequent. The 3-dimensional structure of one of these clones showed typical beta, sheet structure of immunoglobulin chains. CONCLUSION: The IgM transcripts expressed by the B cells in the peripheral blood of KD patients in the acute phase of the disease clearly showed an oligoclonal expansion, suggesting that KD is caused not by stimulation of a superantigen, but rather by a conventional antigen.ope

An Active and Soft Hydrogel Actuator to Stimulate Live Cell Clusters by Self-folding

The hydrogels are widely used in various applications, and their successful uses depend on controlling the mechanical properties. In this study, we present an advanced strategy to develop hydrogel actuator designed to stimulate live cell clusters by self-folding. The hydrogel actuator consisting of two layers with different expansion ratios were fabricated to have various curvatures in self-folding. The expansion ratio of the hydrogel tuned with the molecular weight and concentration of gel-forming polymers, and temperature-sensitive molecules in a controlled manner. As a result, the hydrogel actuator could stimulate live cell clusters by compression and tension repeatedly, in response to temperature. The cell clusters were compressed in the 0.7-fold decreases of the radius of curvature with 1.0 mm in room temperature, as compared to that of 1.4 mm in 37 degrees C. Interestingly, the vascular endothelial growth factor (VEGF) and insulin-like growth factor-binding protein-2 (IGFBP-2) in MCF-7 tumor cells exposed by mechanical stimulation was expressed more than in those without stimulation. Overall, this new strategy to prepare the active and soft hydrogel actuator would be actively used in tissue engineering, drug delivery, and micro-scale actuators

Dispersion of Vascular Plant in An-do, Korea

AbstractThe vascular plants observed in the area were composed of a total of 342 taxa; 104 families, 239 genus, 309 species, 30 varieties, 2 forms and 1 sub-species. The endangered species found in the area were Glehnia littoralis Fr. Schm. and Milletia japonica (Siebold & Zucc.) A.Gray. The five endemic plants were found growing in the area like Carpinus coreana Nakai., Celtis choseniana Nakai, Clematis trichotoma, Spiraea prunifolia for. simpliciflora and Weigela subsessilis L.H.Bailey. Specialized plants of Geumodo were a total of 45 species; 34 taxa in Grade I, 10 taxa in Grade III, and 1 taxon in Grade V. Glehnia littoralis Fr. Schm. and Milletia japonica (Siebold & Zucc.) A.Gray confirmed in this study formed a colony alongside the coast and mountain paths. Currently, the construction to build water supply and sewer systems destroyed part of the colony. Therefore, in the long-term perspective, the conservation plan such as comprehensive research and monitoring on the ecosystem shall be established to protect indeciduous plants in the warm temperate zone

A Score-Based Evaluation Model for Rehabilitation of Existing Pumped Storage Hydropower Plant Construction

As the proportion of new and renewable energy increases, power control demands are becoming more frequent due to variability in power generation. As a complementary means against this, the pumped storage hydropower plants (PSHP) are attracting attention as energy storage systems (ESS), but it has high construction costs. Therefore, this study aims to improve the economic feasibility by developing the evaluation model of the existing infrastructure into an upper/lower dam suitable for PSHP. The concept of upper dam capacity is newly defined, and the evaluation index is constructed using normalization. A new evaluation system is presented for five factors: environment, stability, energy, capacity, and economy. Finally, it is tested in the pilot area in Korea. Several candidates, including the PSHP in operation, are found to have been distributed with higher scores. These results will help to satisfy the selection of candidates during the preliminary feasibility study phase, and programming them will enable more accurate and rapid assessment

Development of Automatic Mold Shot Measurement and Management System for Smart Factory

Many small- and medium-sized car-part manufacturers are either still managing their mold manually or rarely managing it, and therefore, experience significant manufacturing cost and loss in time. In such a situation, a module has been developed in the present work which can count the number of mold used. Such a module is extremely important for small and medium-sized enterprises (SMEs) applying which in the production line they will be able to manage the mold life cycle and improve product quality. This is expected to have both direct and indirect effects on their business activities. The developed system uses a photo sensor, distance measurement sensor, Atmega128 MCU, tablet pc and Bluetooth communication module. The actual module developed in this study was set up on a molding equipment for test and data were collected using an existing tablet PC. The test showed that the number of shots increased when the upper mold touched the lower mold. The maximum and minimum value between the upper and lower molds could be adjusted with the automatic mold shot measurement and management system. Therefore, any molding equipment with various upper-lower gaps will be able to apply the newly developed system