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This paper makes a theoretical contribution by providing clear and detailed derivation of economic agents’ decision problems including elastic labor supply in Gertler’s overlapping generation (OLG) model. We apply the model to the Korean economy by calibration based on Korean economic data. It also analyzes the impact of current social issues such as aging and extension of retirement age, on the Korean economy in a long-run equilibrium. Subsequently, we also discuss the implications of the analysis. Aging has prolonged the period of retirement; therefore, population structure changes by the increase in the proportion of retirees, the total consumption-to- GDP ratio decreases, and capital stock increases due to reduced propensity to consume out of wealth in preparation for an individual’s retirement life. The implementation of retirement age extension increases the proportion of retirees relatively less and alleviates fluctuations in labor supply and the share of financial assets for both economic agents. However, the decrements in consumption-to-GDP ratio is larger than before, and this leads to a larger rise in the capital stock compared to when there is only an aging effect.

We suggest a risk-adjusted valuation approach for workers at retirement risk to make decisions in an overlapping generations economy. The risk-averse workers use greater weights than expected, so-called risk-adjusted probability, on their retirement cash flows to assess the residual lifetime income. This method can be consistently applied to value financial and non-financial assets, and on the risk-adjusted valuations, the workers will make optimal investments. To predict capital returns and economic variables, comparative statics will be numerically implemented via demographic structure, preference, and social security policy by aggregating workers’ decisions.

We suggest an overlapping generations model incorporating the risk-adjusted valuation in a worker’s decision problem. The risk-adjusted probabilities allow risk-averse workers to place more weight on cash flows upon retirement when assessing lifetime income at present value. The risk-adjusted valuation is consistently applied to any non-financial asset, allowing them to be evaluated collectively or separately. We predict capital returns under demographic structure, consumption preference, and social security policy changes.

The effect of co-sputtering condition on the structural properties of thin films grown by RF magnetron co-sputtering system was investigated for manufacturing UV LED. thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The thin films have sufficient crystallinity on the high ZnO power. The EDS analyzed showed that the Mg content in the films decreased from 3.99 to 24.27 at.% as the RF power of ZnO target increased. The Mg content in the films could be controlled by co-sputtering power.

The effect of sputtering condition on the structural properties of ZnO thin films grown by RF magnetron sputtering system was investigated for TFT driver circuit. ZnO thin films were grown with ZnO target varying RF power and working pressure. Structural properties were investigated by X-ray dif-fraction (XRD) and atomic force microscope (AFM). The ZnO thin films have sufficient crystallinity on the 100W RF power. But, the surface roughness of ZnO films was increased as increased RF power. As increased working pressure from 5 mTorr to 15 mTorr, a full width at half maximum (FWHM) of ZnO (002) peak was increased. Keywords: Thin film transistor, Thin film, Oxide semiconductor, Grain size, Atomic Force Microscopy 1. 서 론 최근 선박의 평형을 유지하기 위해 선박에 유입되는 선박평형수(Ballast water)의 처리방법에 소비전력이 적은 자외선 발광 다이오드(UV LED)를 적용하려는 시도가 이루어지고 있다[1]. UV LED 는 AlN 기반의 재료를 사용하여야 하나 격자부정합으로 인한 발광효율이 저하, 온도 민감성, 높은 Al 농도에서의 낮은 성장률 등으로 AlGaN/GaN계를 이용한 UV LED는 제작에 많은 어려움이 있다[2]. 또한 기존의 디스플레이를 대체할 수 있는 투명하고 유연한 특성을 가지는 차세대 투명 플렉시블 디스플레이(transparent flexible display)에 대한 연구가 국내외에서 활발히 진행되고 있다. 플렉시블 디스플레이의 active matrix를 위한 구동소자는 수소화된 비정질 실리콘을 채널 물질로 사용한 박막트랜지스터(hydrogenated amorphous silicon thin film transistor, a-Si:H TFT)가 증착공정이 간단하고 공정비용이 적게들어 주로 사용되고 있다[3].

The effect of co-sputtering condition on the structural properties of thin films grown by RF magnetron co-sputtering system was investigated for manufacturing ZnO/MgZnO structure LED. thin films were grown with ZnO and MgO target varying RF power. Structural properties were investigated by X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). The ZnO thin films have sufficient crystallinity on the high RF power. As RF power of ZnO target increased, the contents of MgO in the film decreased. LED was manufactured using ZnO/MgZnO multi-layer on p-GaN/ substrate. Threshold voltage of multi-layer LED was appeared at 8 V, and it was luminesced at wave length of 550 nm.

A 40GHz PLL synthesizer is designed in 65nm CMOS for a 60GHz sliding-IF RF transceiver for IEEE 802.11ad applications. For wide locking range, ILFD employs a 5-bit switched capacitor array and a inductive peaking at the injection FET. The ILFD's locking range is wider than the VCO's tuning range, which ensures the PLL can safely lock across the VCO's full tuning range. Also, a tuned buffer with a boosted Q load is employed to minimize unwanted interaction between the VCO and ILFD's operating frequencies, which also helps widen the PLL's locking range. The PLL synthesizer is designed in 65nm CMOS and its die area is 1.0×1.1mm2.

A two-point tuning VCO with switchable secondary tuning gain K VCO2 is designed in 65㎚ CMOS for a two-point modulation PLL-based phase modulator that is to serve as phase-modulating part of a quad-band GSM/GPRS/EDGE polar transmitter. The two-point tuning VCO employs two varactor banks for dual tuning capability. The second varactor bank is a differentially tuned structure and its gain K VCO2 is switchable to minimize its variation for maintaining optimum second-point modulation gain. Fabricated in 65㎚ CMOS, the VCO draws 8 ㎃ from 2 V supply. It covers the 2930 ? 4150 ㎒. The phase noise is -142㏈Bc/㎐ at 10㎒ offset for 3.9 ㎓ output frequency. The silicon area of the VCO and accompanying dividers is 810 x 600 ㎛².

The increasing volumes of relational data let us find an alternative to cope with them. Recently, several hybrid approaches (e.g., HadoopDB and Hive) between parallel databases and Hadoop have been introduced to the database community. Although these hybrid approaches have gained wide popularity, they cannot avoid the choice of suboptimal execution strategies. We believe that this problem is caused by the inherent limits of their architectures. In this demo, we present Tajo, a relational, distributed data warehouse system on shared-nothing clusters. It uses Hadoop Distributed File System (HDFS) as the storage layer and has its own query execution engine that we have developed instead of the MapReduce framework. A Tajo cluster consists of one master node and a number of workers across cluster nodes. The master is mainly responsible for query planning and the coordinator for workers. The master divides a query into small tasks and disseminates them to workers. Each worker has a local query engine that executes a directed acyclic graph of physical operators. A DAG of operators can take two or more input sources and be pipelined within the local query engine. In addition, Tajo can control distributed data flow more flexible than that of MapReduce and supports indexing techniques. By combining these features, Tajo can employ more optimized and efficient query processing, including the existing methods that have been studied in the traditional database research areas. To give a deep understanding of the Tajo architecture and behavior during query processing, the demonstration will allow users to submit TPC-H queries to 32 Tajo cluster nodes. The web-based user interface will show (1) how the submitted queries are planned, (2) how the query are distributed across nodes, (3) the cluster and node status, and (4) the detail of relations and their physical information. Also, we provide the performance evaluation of Tajo compared with Hive.