• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.558-567
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• 2016

In the case of France which was successful in improving the ultra-low fertility rates of birth and South Korea, from the late 1980s, the birth rate fell continuously. In 1994, total fertility rate fell 1.66, but thanks to the active family policy of the government in the mid 1990s, it grew and maintained 2.0 average since the year 2008 until now. This study examined carefully how France was not classified as advanced welfare state, overcame the obstacles of low fertility problem in the socio-economic and institutional side and trying to get some suggestions from South Korea in which it of such problems in the field of low fertility.

• Journal of the Korean Geographical Society
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• v.44 no.5
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• pp.634-646
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• 2009

This paper critically examines cluster dynamics and development in a multi-scalar approach, criticizing both the argument overemphasizing local networks and endogenous development for regional development and the contention highlighting global networks and the role of global players. We argue that state policies, exogenous and direct, play a significant part in cluster dynamics and development especially in the case of Korea where the state government's strong policies have led to rapid industrialization. We analyze multi-scalar factors, especially the government policies at a national level, in the development paths of the three cases including Ulsan automobile cluster, Daedeok research cluster, and Dongdaemun fashion cluster.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.121-121
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• 2010

The water resources of the United States are increasingly at risk and the nation's water policy is in serious difficulty. Water resources protection laws primarily passed since 1950 often contradict water resources development laws passed before 1950. These contradictions complicate efficient and effective responses to the nation's water resources challenges including climate change, our aging infrastructures, changing population dynamics, drought, floods, wetlands and aquatic species loss, ecosystem restoration and many others. In addition, water law and policy determination, management and enforcement are so broadly distributed between, local, state and federal responsibilities that effective responses again are difficult. For example, at the national level alone, more than a dozen federal agencies have water resources responsibilities including resource development, resource assessment, and resource protection. They are presided over by six cabinet (Ministerial) departments, at least 13 congressional (parliamentarian) committees and 23 subcommittees, and are funded by five appropriations subcommittees. Lastly, good science and the public accountability associated with it are often overshadowed by political considerations at local, state and federal levels. The United States approach to solving water resources challenges is ad hoc - we address problems as they appear or as they merit political support rather than using good science to address our long term water resources needs.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1740-1751
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• 2018

This paper proposes a novel fault tolerant tracking control (FTTC) scheme for a class of nonlinear systems with actuator failures based on the policy iteration (PI) algorithm and the adaptive fault observer. The estimated actuator failure from an adaptive fault observer is utilized to construct an improved performance index function that reflects the failure, regulation and control simultaneously. With the help of the proper performance index function, the FTTC problem can be transformed into an optimal control problem. The fault tolerant tracking controller is composed of the desired controller and the approximated optimal feedback one. The desired controller is developed to maintain the desired tracking performance at the steady-state, and the approximated optimal feedback controller is designed to stabilize the tracking error dynamics in an optimal manner. By establishing a critic neural network, the PI algorithm is utilized to solve the Hamilton-Jacobi-Bellman equation, and then the approximated optimal feedback controller can be derived. Based on Lyapunov technique, the uniform ultimate boundedness of the closed-loop system is proven. The proposed FTTC scheme is applied to reconfigurable manipulators with two degree of freedoms in order to test the effectiveness via numerical simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.1
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• pp.145-164
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• 2023

Cloud computing offers a platform that is both adaptable and scalable, making it ideal for outsourcing data for sharing. Various organizations outsource their data on cloud storage servers for availing management and sharing services. When the organizations outsource the data, they lose direct control on the data. This raises the privacy and security concerns. Cryptographic encryption methods can secure the data from the intruders as well as cloud service providers. Data owners may also specify access control policies such that only the users, who satisfy the policies, can access the data. Attribute based access control techniques are more suitable for the cloud environment as they cover large number of users coming from various domains. Multi-authority attribute-based encryption (MA-ABE) technique is one of the propitious attribute based access control technique, which allows data owner to enforce access policies on encrypted data. The main aim of this paper is to comprehensively survey various state-of-the-art MA-ABE schemes to explore different features such as attribute and key management techniques, access policy structure and its expressiveness, revocation of access rights, policy updating techniques, privacy preservation techniques, fast decryption and computation outsourcing, proxy re-encryption etc. Moreover, the paper presents feature-wise comparison of all the pertinent schemes in the field. Finally, some research challenges and directions are summarized that need to be addressed in near future.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.2
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• pp.105-122
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• 1994

The landscape plannings were composed of the fundamental provisions which are important factors for the city and local plannings in Germany. The State Government run institute like LOLF in NRW have been established to solve the serious ecological problems. The institute have completed the basic system covering various ecological problems, such as environmental affection analysis and ecological risk, to contribute the application of the various land-using plants. The ecological landscape plannings are regarded as major fundamental plans of environmental preservation for the plannings development. The problems about the local landscape plannings needed to be preserved ecologically are introduced into the Federal Nature Preservation Law and State Congress Law in order to carry out the environmental protection policy effectively. The local landscape plannings are divided into two-step models by the special classification system for the planning. One is build-up of an independent design separated from city plans functionally, and the other is a systematic regulation for cooperation between the local plans and ecological conservation functions. The local plannings including lands to be preserved as the Nature Preservatin Zone is classified a rest area total sectioned plains.

• Journal of the Korean Statistical Society
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• v.31 no.4
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• pp.491-507
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• 2002

We analyze a single server bulk input queue with optional server vacations under a single vacation policy and balking phenomenon. The service times of the customers as well as the vacation times of the server have been assumed to be arbitrary (general). We further assume that not all arriving batches join the system during server's vacation periods. The supplementary variable technique is employed to obtain time-dependent probability generating functions of the queue size as well as the system size in terms of their Laplace transforms. For the steady state, we obtain probability generating functions of the queue size as well as the system size, the expected number of customers and the expected waiting time of the customers in the queue as well as the system, all in explicit and closed forms. Some special cases are discussed and some known results have been derived.

• KIEE International Transactions on Power Engineering
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• v.4A no.3
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• pp.159-166
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• 2004

Forecasting prices in electricity markets is critical for consumers and producers in planning their operations and managing their price risk. We utilize the generalized autoregressive conditionally heteroskedastic (GARCH) method to forecast the electricity prices in two regions of New York： New York City and Central New York State. We contrast the one-day forecasts of the GARCH against techniques such as dynamic regression, transfer function models, and exponential smoothing. We also examine the effect on our forecasting of omitting some of the extreme values in the electricity prices. We show that accounting for the extreme values and the heteroskedactic variance in the electricity price time-series can significantly improve the accuracy of the forecasting. Additionally, we document the higher volatility in New York City electricity prices. Differences in volatility between regions are important in the pricing of electricity options and for analyzing market performance.

• Journal of Arbitration Studies
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• v.28 no.2
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• pp.201-216
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• 2018

After the adoption of the Lisbon Treaty, the European Union's Common Commercial Policy now belongs to the exclusive competence area of the EU, including the foreign direct investment (FDI) policy. Regarding the bilateral investment protection treaties (BITs) between the EU Member States, the European Commission is of the view that such BITs should be discarded. On March 6, 2018, the Court of Justice of the European Union (CJEU) held in the Achmea BV v. Slovakia case that a BIT between the EU Member States, as well as arbitral awards based on that BIT, is not subject to request for preliminary rulings under the Treaty on the Functioning of the European Union (TFEU), and thus they are not compatible with the EU law. However, the judgment did not silence the controversy. Instead, many people questioned the legal reasoning and the legitimacy of judgment, and therefore the problem is still ongoing.

• Journal of the military operations research society of Korea
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• v.16 no.1
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• pp.142-150
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• 1990

This paper combines research in the areas of replacement and machine interference. Although over the past three decades there has been a great deal of research in the area of optimal replacement for stochastically deteriorating equipment and research dealing with machine interference problems : there has been a lack of research when these two areas are combined. However, the melding of these two well-known areas yields a very practical problem which demands theoretical investigation. In this paper we derive the steady state probabilities with a control limit policy for a two-machine one repairman problem. The control policy is a simple age dependent control described by the control limit, $t^{*}$. Once $t^{*}$ is fixed, the steady state probabilites that one, two, and no machines are working will be obtained.