• International journal of advanced smart convergence
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• 제7권4호
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• pp.19-26
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• 2018

One of the distinct features of Wireless Sensor Networks (WSNs) is duty cycling mechanism, which is used to conserve energy and extend the network lifetime. Large duty cycle interval introduces lower energy consumption, meanwhile longer end-to-end (E2E) delay. In this paper, we introduce an energy consumption minimization problem for duty-cycled WSNs. We have applied Q-learning algorithm to obtain the maximum duty cycle interval which supports various delay requirements and given Delay Success ratio (DSR) i.e. the required probability of packets arriving at the sink before given delay bound. Our approach only requires sink to compute Q-leaning which makes it practical to implement. Nodes in the different group have the different duty cycle interval in our proposed method and nodes don't need to know the information of the neighboring node. Performance metrics show that our proposed scheme outperforms existing algorithms in terms of energy efficiency while assuring the required delay bound and DSR.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1223-1231
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• 2018

The direct torque control (DTC) scheme features a simple structure thanks to stator flux-oriented control. It has the advantage of robustness against motor parameters variation since only the stator resistance is involved in the control scheme. On the other hand, the disadvantage of DTC is large torque ripple. To reduce the torque ripple, many studies on DTC-space vector modulation (DTC-SVM) schemes, which modulate the duty ratio with a fixed switching cycle, have been proposed. However, there is the difficulty in obtaining the duty ratio for DTC-SVM. Hence, this paper proposes a new duty ratio selection and stator flux calculation methods for reducing torque ripple. Simulations and experiments were carried out to determine the validity of the proposed method. The proposed scheme has simplified the duty ratio command and achieved the same control performance as the conventional duty ratio modulation method without using the information of motor parameters.

• 통상정보연구
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• 제10권3호
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• pp.143-162
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• 2008

The Title 19 of the U.S. Code covers custom duties and is the heart of international trade regulation in the U.S.. Among the provisions in Title 19, is Chapter 4, the Tariff Act of 1930. Under U.S. Antidumping duty law, dumping occurs when `subject merchandise' is imported into the U.S. and sold at less than `fair value.' The administration of U.S. Antidumping duty law is shared between the Department of Commerce('Commerce') and International Trade Commission('USITC'). The U.S. Court of International Trade ("CIT") and the U.S. Court of Appeals for the Federal Circuit ("CAFC") decided the review of antidumping duty ("AD") determinations and administrative review results issued by the Commerce and the USITC, as well as the review of countervailing duty ("CVD") decisions. In Eurodif S.A. v. United States, the CAFC considered the important issue of whether the antidumping and countervailing duty laws apply to sales and purchases of services--in this case, the sale or purchase of enrichment services. Although the federal courts had considered the issue of whether a sale of enrichment services constitutes a sale of goods, the issue had never arisen in the context of the antidumping and countervailing duty laws. Also this is the first time that the Supreme Court has ever agreed to consider an antidumping case.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권1호
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• pp.105-122
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• 2011

The fundamental design goal of wireless sensor MAC protocols is to minimize unnecessary power consumption of the sensor nodes, because of its stringent resource constraints and ultra-power limitation. In existing MAC protocols in wireless sensor networks (WSNs), duty cycling, in which each node periodically cycles between the active and sleep states, has been introduced to reduce unnecessary energy consumption. Existing MAC schemes, however, use a fixed duty cycling regardless of multi-hop communication and traffic fluctuations. On the other hand, there is a tradeoff between energy efficiency and delay caused by duty cycling mechanism in multi-hop communication and existing MAC approaches only tend to improve energy efficiency with sacrificing data delivery delay. In this paper, we propose two different MAC schemes (ADS-MAC and ELA-MAC) using closed-loop control in order to achieve both energy savings and minimal delay in wireless sensor networks. The two proposed MAC schemes, which are synchronous and asynchronous approaches, respectively, utilize an adaptive timer and a successive preload frame with closed-loop control for adaptive duty cycling. As a result, the analysis and the simulation results show that our schemes outperform existing schemes in terms of energy efficiency and delivery delay.

• Journal of Power Electronics
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• 제12권6호
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• pp.886-894
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• 2012

This paper presents a secondary-side, dual-mode feedback LLC resonant controller IC with dynamic PWM dimming for LED backlight units. In order to reduce the cost, master and slave outputs can be generated simultaneously with a single LLC resonant core based on dual-mode feedback topologies. Pulse Frequency Modulation (PFM) and Pulse Width Modulation (PWM) schemes are used for the master stage and slave stage, respectively. In order to guarantee the correct dual feedback operation, Phased-Locked Loop (PLL)-based automatic duty control circuit is proposed in this paper. The chip is fabricated using $0.35{\mu}m$ Bipolar-CMOS-DMOS (BCD) technology, and the die size is $2.5mm{\times}2.5mm$. The frequency of the gate driver (GDA/GDB) in the clock generator ranges from 50 to 425 kHz. The current consumption of the LLC resonant controller IC is 40 mA for a 100 kHz operation frequency using a 15 V supply. The duty ratio of the slave stage can be controlled from 40% to 60% independent of the frequency of the master stage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.1849-1876
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• 2022

Wireless Sensor Network (WSN) is considered as an integral part of the Internet of Things (IoT) for collecting real-time data from the site having many applications in industry 4.0 and smart cities. The task of nodes is to sense the environment and send the relevant information over the internet. Though this task seems very straightforward but it is vulnerable to certain issues like energy consumption, delay, throughput, etc. To efficiently address these issues, this work develops a cross-layer model for the optimization between MAC and the Network layer of the OSI model for WSN. A high value of duty cycle for nodes is selected to control the delay and further enhances data transmission reliability. A node measurement prediction system based on the Kalman filter has been introduced, which uses the constraint based on covariance value to decide the scheduling scheme of the nodes. The concept of duty cycle for node scheduling is employed with a greedy data forwarding scheme. The proposed Duty Cycle-based Greedy Routing (DCGR) scheme aims to minimize the hop count, thereby mitigating the energy consumption rate. The proposed algorithm is tested using a real-world wastewater treatment dataset. The proposed method marks an 87.5% increase in the energy efficiency and reduction in the network latency by 61% when validated with other similar pre-existing schemes.

• 무역상무연구
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• 제71권
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• pp.171-194
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• 2016

In the UK, the legal principle for the duty of disclosure established in Carter v Boehm case was codified in the Marine Insurance Act 1906("MIA"). The duty of disclosure under the MIA is the pre-contractual duty by the insured and therefore, the insured should disclose the every material circumstance that would influence a prudent insurer's judgement. If the insured violates the duty of disclosure, the insurer is entitled to avoid the insurance contract, regardless of whether there was the deliberate or reckless breach, which is unfavorable to the insured. The Law Commission reviewed the duty of disclosure under the MIA in detail and provided the Insurance Act 2015 for the purpose of enhancing the interests of the insured. The Insurance Act 2015("Act"),while the basic legal structure of the duty of disclosure under the MIA still remains, amends it in respect of non-consumer insurance and furthermore, integrate the duty of disclosure and the duty not to misrepresent into the duty of fair presentation of risk. And according to the Act, the insurer is required to more actively communicate with the insured before entering the contract with the result that, if the insured fails to disclose the material circumstance but provides the sufficient information to put the insurer on notice, the insurer should further inquire for the purpose of the insured's revealing the material circumstance. In addition, the Act details the insured's constructive knowledge of material circumstance by reviewing the current case law and introduces a new system for the insurer's proportionate remedy against the insured's breach of the duty of fair presentation of risk.

• 한국통신학회논문지
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• 제39B권10호
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• pp.691-699
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• 2014

네트워크 수명을 연장시키기 위해 무선 센서 네트워크에서는 idle listening에 소비되는 에너지를 줄일 수 있는 듀티-사이클 MAC 프로토콜들이 제안되었다. 일반적인 듀티-사이클 MAC 프로토콜에서 각 센서 노드는 잔여 에너지양을 기반으로 듀티-사이클 주기를 계산한다. 그러나 에너지 수집이 가능한 센서 네트워크에서 기존 듀티-사이클 주기는 에너지 수집률이 높은 센서 노드에 불필요한 sleep 지연을 발생시킨다. 따라서 우리는 이전 연구에서 잔여 에너지양과 에너지 수집률을 함께 고려하여 듀티 사이클-주기를 조절하는 듀티-사이클 스케줄링 기법을 제안하였다. 그러나 이러한 듀티-사이클 MAC 프로토콜들은 듀티 사이클-주기 변화에 따른 성능 차이를 고려하지 않고 듀티-사이클 주기를 항상 선형적으로 조절하므로, 응용의 요구사항에 맞는 최적의 듀티 사이클 주기를 얻지 못한다. 본 논문에서는 듀티-사이클 주기를 계산하는 세 가지 기법들을 제안하고 그 결과에 대해 분석한다. 실험을 통해 제안된 기법들이 기존 듀티-사이클 스케줄링 기법에 비해 네트워크 수명, 단대단 패킷 전송 시간과 패킷 전송률을 각각 최대 23%, 44%, 31% 증가시킴을 확인하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.331-334
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• 2004

본 논문에서는 클록의 duty ratio가 변하였을 때, 그 클록의 duty ratio를 $50\%$의 duty ratio로 만들어 주는 Pulse Width Control Loop Circuit을 설계하였다. 기존의 논문에서는 duty ratio를 변화시키기 위해 각 duty ratio 마다 알맞은 제어 전압을 공급해하는 문제점이 있었다. 본 논문은 제어 전압이 변하지 않고 일정한 전압으로도 duty ratio를 변화시킬 수 있게 하여, 제어 전압 변화에 대한 문제점을 해결하였다. 설계, 시뮬레이션 결과 기존의 논문보다 간단해진 회로 구성으로 더욱 높은 주파수에서 동작하였다. 그리고 settling 시간도 기존의 논문의 l00ns 이상에서 5ns로 줄어듦을 확인할 수 있었다. 본 논문은 3.3V의 공급 전압에서 $0.35{\mu}m$ CMOS공정을 이용하여 설계하였고 동작 주파수는 500MHz-2GHz였고, settling 시간은 10n이하였다.

• 무역상무연구
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• 제14권
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• pp.103-152
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• 2000

English contract law has traditionally taken the view that it is not the duty of the parties to a contract to give information voluntarily to each other. In English law, one of the principal distinctions between insurance contract law and general contract law is the existence of the doctrine of utmost good faith in insurance law. The doctrine gives rise to a variety of duties, some of which apply before formation of the contract while others apply post-formation. This article is, therefore, designed to analyse the overall structure and problems of the doctrine of utmost good faith in English marine insurance law. The results of analysis are as following : First, the requirement of utmost good faith in marine insurance law arises from the fact that many of the relevant circumstances are within the exclusive knowledge of the assured and it is impossible for the insurer to obtain the facts to make a appropriate calculation of the risk that he is asked to assume without this information. Secondly, the duty of utmost good faith provided in MIA 1906, s. 17 has the nature as a bilateral or reciprocal, overriding and absolute duty. Thirdly, the Court of Appeal in Skandia held that breach of the pre-formation duty of utmost good faith did not sound in damages since the duty did not arise out of an implied contractual term and the breach did not constitute a tort. Instead, the Court of Appeal held that the duty was an extra-contractual duty imposed by law in the form of a contingent condition precedent to the enforceability of the contract. Fourthly, the scope of the duty of utmost good faith is closely related to the test of materiality and the assured is required to disclose only material circumstances subject to MIA 1906, s. 18(1) and 20(1). The test of materiality, which had caused a great deal of debate in English courts over 30 years, was finally settled by the House of Lords in Pan Atlantic and the House of Lords rejected the 'decisive influence' test and the 'increased risk' test, and the decision of the House of Lords is thought to accept the 'mere influence' test in subsequent case by the Court of Appeal. Fifthly, the insurer is, in order to avoid contract, required to provide proof that he is induced to enter into the contract by reason of the non-disclosure or misrepresentation of the assured. Sixthly, the duty of utmost good faith is, in principle, terminated before contract is concluded, but it is undoubtful that the provision under MIA 1906, s. 17 is wide enough to include the post-formation duty. The post-formation duty is, however, based upon the terms of marine insurance contract, and the duty lies entirely outside s. 17. Finally, MIA 1906, s. 17 provides expressly for the remedy of avoidance of the contract for breach of the duty. This means rescission or retrospective avoidance of the entire contract, and the remedy is based upon a fairly crude 'all-or-nothing' approach. What is needed in English marine insurance law is to introduce a more sophiscated or proportionate remedy.