• Journal of Institute of Control, Robotics and Systems
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• v.19 no.6
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• pp.563-568
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• 2013

The purpose of this study is to find the analytic solution for determining the optimal capacity (lot-size) of a batch-storage network to meet the finished product demand under infrequent shutdowns. Batch processes are bound to experience random but infrequent operating time losses. Two common remedies for these failures are duplicating another process or increasing the process and storage capacity, both of which are very costly in modern manufacturing systems. An optimization model minimizing the total cost composed of setup and inventory holding costs as well as the capital costs of constructing processes and storage units is pursued with the framework of a batch-storage network of which flows are susceptible to infrequent shutdowns. The superstructure of the plant consists of a network of serially and/or parallel interlinked batch processes and storage units. The processes transform a set of feedstock materials into another set of products with constant conversion factors.A novel production and inventory analysis method, the PSW (Periodic Square Wave) model, is applied. The advantage of the PSW model stems from the fact it provides a set of simple analytic solutions in spite of a realistic description of the material flow between processes and storage units. The resulting simple analytic solution can greatly enhance a proper and quick investment decision at the early plant design stagewhen confronted with diverse economic situations.

• Journal of the Korea Safety Management & Science
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• v.24 no.3
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• pp.29-37
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• 2022

The development of technology related to the Fourth Industrial Revolution and the growth of the online market due to pandemic are continuing the growth of the logistics market for product delivery. If it is difficult to deliver the product directly to the customer during delivery, storage and delivery using the unmanned courier box are being carried out. However, existing storage boxes are not actively used due to lack of usability even though they have the advantage of storing goods and delivering non-face-to-face. In addition, existing courier boxes are not prepared for cold chain transportation. The unmanned delivery storage device with ICT cold chain technology should be developed to prepare for the transition to non-face-to-face society, to improve logistics efficiency and meet user's requirements. Also, it is necessary to consider the measures to reduce the safety problems that may occur during the use and maintenance of the automatic system. This study conducted a model-based analysis for the development of unmanned delivery storage devices with ICT cold chain technology, and conducted a study to derive the system development specifications that meet the requirements and secure safety and apply them to the development process.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.4
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• pp.531-541
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• 2023

The Wolsong Nuclear Power Plant (NPP) operates an on-site spent fuel dry storage facility using concrete silo and vertical module systems. This facility must be safely maintained until the spent nuclear fuel (SNF) is transferred to an external interim or final disposal facility, aligning with national policies on spent nuclear fuel management. The concrete silo system, operational since 1992, requires an aging management review for its long-term operation and potential license renewal. This involves comparing aging management programs of different dry storage systems against the U.S. NRC's guidelines for license renewal of spent nuclear fuel dry storage facilities and the U.S. DOE's program for long-term storage. Based on this comparison, a specific aging management program for the silo system was developed. Furthermore, the facility's current practices-periodic checks of surface dose rate, contamination, weld integrity, leakage, surface and groundwater, cumulative dose, and concrete structure-were evaluated for their suitability in managing the silo system's aging. Based on this review, several improvements were proposed.

• Transactions of the Society of Information Storage Systems
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• v.11 no.1
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• pp.1-5
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• 2015

The selective frequency analysis method is suggested in the holographic data storage system with the nyquist aperture to reduce the size of hologram. The image filter was designed with many different methods to improve the bit error rate caused by the nyquist aperture. In previous the methods of image restoration for HDS, an iteration time and a highly precise point spread function were necessary. In this paper, we describe the optical system with analytic method. Thereby, we expect our result help the researchers to design the filter.

• Transactions of the Society of Information Storage Systems
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• v.8 no.2
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• pp.67-71
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• 2012

Page-oriented holographic data storage (HDS) is very sensitive to the tilt error. Therefore, tilt error should be measured and compensated. Especially, mechanical tilt measurement method cannot cope with tilt error measurement because photopolymer medium has shrinkage problem. Therefore, the method to solve this problem is using the reconstructed image which can represent both tilt and shrinkage effect. In this paper, we suggest disc tilt measurement algorithm using image pattern of retrieval data.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.1
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• pp.1-13
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• 2013

Some systems such as missiles and ammunitions are used only one time in combat or emergency situation. Predicting correct storage reliability is very important for those systems which are inspected periodically. Many researches have been done for predicting the storage reliability using generally exponential or Weibull failure distribution. However, recent studies show the hazard functions follow various types of failure distributions. So in this paper, we proposed a generalized model that measures the storage reliability regardless of type of failure distributions. And this model reflects inspection error and failures that might be occurred during periodical check and within storage term as well.

• The KIPS Transactions:PartA
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• v.12A no.7 s.97
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• pp.605-612
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• 2005

With the increase in I/O performance and capacity, it becomes commonplace that storage systems are shared by multiple storage users. This paper proposes an efficient token-bucket-based performance control technique for the shared storage that can statistically guarantee demanded storage performance from different users. It also verifies the operational characteristics and performance of the proposed scheme under various types of I/O workloads.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.9
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• pp.727-735
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• 2003

The determination of completion time constitutes an important step in developing algorithms for short-term production scheduling. Existing completion time algorithms of multi-product batch processes often assume that intermediate storage tanks are always available when it is needed. In this paper, we consider a serial multi-product batch plants with ZW and NIS policy intermediate storge tank. We limit storage residence time and allocated products in the intermediate storage tank to minimize the quality change of the stored material as well as to reduce the clearing time during product change. A set of recurrence relations is suggested to calculate the completion times for the given batch sequence of products on all processing units. Also analytic solution for the suggested model is solved by a graphical method. The effectiveness of these results is proved by a few illustrative examples.

• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.59-65
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• 2007

Scanning Prove Microscope (SPM) - based Data Storage (SDS)는 Atomic Force Microscope (AFM)을 이용하여 Cantilever Tip 이 저장 장치 미디어에 나노미터 단위로 비트를 읽고, 쓰고 지우는 저장 장치로써, x, y 두 축을 이용한다. 따라서 축간 coupling 의 영향이 크게 발생한다. 따라서 축간 coupling 의 영향을 고려하여 제어기를 설계하여야 한다. 본 논문은 coupling 요소를 제거하기 위하여 Feedforward Decoupler 를 설계하여 Stage 의 입력 앞 단에 추가하는 방법을 제안하였다. Feedforward Decoupler 를 추가함으로써 coupling 요소가 줄어드는 것을 모의 실험을 통해 확인한다. 이를 통해 나노급으로 보다 정밀한 제어가 가능함을 확인하였다.

• Transactions of the Society of Information Storage Systems
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• v.3 no.2
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• pp.73-80
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• 2007

Atomic Force Microscopy (AFM)방식을 이용한 Scanning probe Data Storage (SDS) 시스템은 array cantilever 를 이용하여 나노 단위로 데이터 읽기, 쓰기를 하는 시스템이다. 따라서 미디어가 있는 stage 의 x 축과 y 축 및 두 축간 coupling 을 고려한 제어기 설계가 요구된다. 본 논문은 SDS 시스템의 축간 coupling 을 고려하지 않은 기존의 제안된 LQG 에 PI 를 추가한 제어기 구조를 사용한다. 두 축간 coupling 공진의 영향을 최소화 하기 위해 convex optimization 으로 설계된 최적의 position profile를 기준 입력신호로 사용한다. 제안된 제어기를 SDS 시스템에 적용하여 모의실험을 하고 그 결과 position profile 로 인해 각 축간 coupling 공진 영향이 감소하여 tracking performance 가 기존의 LQG 제어기 보다 향상된 것을 확인한다.