6,471 research outputs found

    Does the Korean economy depend too much on Samsung?

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    Kinematic synthesis of mechanisms for multiply separated positions

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    The rigid body motion is studied in a combination of finitely and infinitesimally separated positions in planar, spherical, and spatial kinematics. A general new method for determining the locations of points and/or lines in a rigid body moving through finitely and infinitesimally separated positions is developed. These points and/or lines would satisfy the constraints of various types of binary links for planar, spherical, and spatial mechanisms. A unified form of circle-point curve equation is derived for finitely and multiply separated position problems in planar and spherical motions. A graphical method to construct the circle-point and center-point curves and Ball point is also investigated for the PP-PP multiply separated positions problem in planar motion. Instantaneous geometric motion of a rigid body is studied in terms of the instantaneous screw axis for the infinitesimally separated positions in spatial kinematics. Also the finite spatial motion problem is recast in terms of determining the screw parameters directly

    Essays on finance, investment, and money

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    Three chapters in this dissertation revolve around the areas of empirical corporate finance and behavioral finance, with particular focuses on firmsā€™ R&D financing, the manager side of behavioral finance, and the effect of network formations on media of exchange. Chapter 2 examines the effects of the financial side of the firm on labor. These effects have not been studied extensively. Using the system Generalized Method of Moments, fixed effects, and IV models, this chapter shows that balance sheet liquidity (cash holdings) can help maintain stable employment in response to demand shocks. Chapter 3 implements human-subject experiments. It shows how contrast effects from psychology studies influence investment and financing decisions. This chapter illustrates that individuals exposed to a positive stimulus amplify risk-seeking in investment decisions compared to individuals exposed to a negative stimulus. However, exposure to positive or negative stimuli does not affect financing decisions. It is likely that financing decisions require a high cognitive load, so they are less affected by emotions. Chapter 4 examines how different types of trade networks influence the emergence of one or more types of money. Many new types of monetary networks have emerged such as cryptocurrency networks. However, the underlying reason for the emergence of new money types is not well understood. Using an agent-based computer model, this chapter shows that the emergence of multiple goods as media of exchange depends on the network structure governing trade between agents

    Development of Wireless Sensor Node for Landslide Detection

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    Landslides have frequently occurred on natural slopes during periods of intense rainfall. With a rapidly increasing population on or near steep terrain in Korea, landslides have become one of the most significant natural hazards. Thus, it is necessary to protect people from landslides and to minimize the damage of houses, roads and other facilities. To accomplish this goal, many landslide prediction methods have been developed around the world. In this study, a prototype of landslide detection is introduced. This system is based on the wireless sensor network (WSN) that is composed of sensor nodes, gateway, and server system. Sensor nodes comprising sensing and communication part are implemented to detect ground movement. A sensing part is designed to measure inclination angle and acceleration accurately, and a communication part is deployed with Bluetooth (IEEE 802.15.1) module to transmit the data to the gateway. To verify the feasibility of this landslide prediction system, a series of experimental studies was performed at a small-scale earth slope equipped with an artificial rainfall dropping device. It is found that sensing nodes planted at slope can detect the ground motion when the slope starts to move. It is expected that the prototype of landslide detection can provide early warnings when landslides occurs

    Hyperinvariant subspaces for quasinilpotent operators on Hilbert spaces

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    AbstractIn this paper, we employ the model theory due to C. Foias and C. Pearcy and the notion of Enflo's extremal vectors of quasinilpotent operators to study the hyperinvariant subspace problem for quasinilpotent operators. Our main result is that if a quasinilpotent quasiaffinity T has a sequence of ā€œc-eigenvectorsā€ xn of TnTāˆ—n such that the set cl{xn:nāˆˆN} is compact, then T has a nontrivial hyperinvariant subspace

    Recent progress in mitochondria-targeted drug and drug-free agents for cancer therapy

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    The mitochondrion is a dynamic eukaryotic organelle that controls lethal and vital functions of the cell. Being a critical center of metabolic activities and involved in many diseases, mitochondria have been attracting attention as a potential target for therapeutics, especially for cancer treatment. Structural and functional differences between healthy and cancerous mitochondria, such as membrane potential, respiratory rate, energy production pathway, and gene mutations, could be employed for the design of selective targeting systems for cancer mitochondria. A number of mitochondria-targeting compounds, including mitochondria-directed conventional drugs, mitochondrial proteins/metabolism-inhibiting agents, and mitochondria-targeted photosensitizers, have been discussed. Recently, certain drug-free approaches have been introduced as an alternative to induce selective cancer mitochondria dysfunction, such as intramitochondrial aggregation, self-assembly, and biomineralization. In this review, we discuss the recent progress in mitochondria-targeted cancer therapy from the conventional approach of drug/cytotoxic agent conjugates to advanced drug-free approaches
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