Browsing by Author "Chang, Yu-Jen"

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A COMMON CYCLE APPROACH FOR SOLVING THE ECONOMIC LOT AND INSPECTION SCHEDULING PROBLEM
(2012-02-01)
Yao, Ming-Jong
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Chen, Shih-Chieh
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Chang, Yu-Jen
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運輸與物流管理系註：原交通所+運管所
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Department of Transportation and Logistics Management
In this study, we consider an imperfect production system in which the manager not only faces the Economic Lot Scheduling Problem, but also needs to conduct multiple inspections during a production lot of any product. Inspection plays an important role in an imperfect production system since it saves the cost from producing and restoring defective items though it also incurs extra inspection cost at the same time. In this study, we employ the common cycle approach in which all the products share the same replenishment cycle, and adopt a consensus inspection policy. The focus of this study is to determine the optimal cycle time and an optimal production and inspection schedule that minimize the total cost per unit time. We formulate a mathematical model in which we take into accounts both the production capacity and inspection capacity constraints. Also, we conduct full theoretical analysis and propose an effective search algorithm for solving an optimal solution. Our numerical experiments demonstrate the effectiveness of the proposed search algorithm.
Disparate mesenchyme-lineage tendencies in mesenchymal stem cells from human bone marrow and umbilical cord blood
(2006-03-01)
Chang, Yu-Jen
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Shih, Daniel Tzu-Bi
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Tseng, Ching-Ping
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Hsieh, Tzu-Bou
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Lee, Don-Ching
Bone marrow and umbilical cord blood are reported to be the main sources of mesenchymal stem cells (MSCs), which have been proposed for many clinical applications. This study evaluated and quantitated the differentiation potential of bone marrow-derived MSCs (bmMSCs) and cord blood-derived MSCs (cbMSCs) by in vitro induction. Results indicated that cbMSCs had a significantly stronger osteogenic potential but lower capacity for adipogenic differentiation than bmMSCs. Leptin, an important regulator of mesenchymal differentiation, has a significantly stronger effect of promoting osteogenesis and inhibiting adipogenesis in bmMSCs than in cbMSCs. Moreover, Cbfa1 mRNA expression in bmMSCs and cbMSCs was affected to different degrees by leptin during osteogenesis. In contrast, leptin reduced PPAR gamma 2 mRNA expression to the same level during adipogenesis in both types of MSCs. These results demonstrate the disparate capacities of MSCs from bone marrow and cord blood and suggest that they be used differently in experimental and therapeutic studies. In addition, the disparate differentiation tendencies of MSCs from different sources should be considered in further applications.
Fast Handover Techniques for ESS-Subnet Topology Mismatch in IEEE 802.11
(2013)
Tseng, Chien-Chao
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Lin, Chia-Liang
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Chang, Yu-Jen
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Yen, Li-Hsing
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資訊工程學系
With the advances in wireless communication technology, mobile applications are gradually being introduced as part of our life. IEEE 802.11 is one of the most popular wireless communication technologies. Prior studies toward layer-2 and layer-3 handoffs assume that Extend Service Set (ESS) exactly matches a dedicated subnet. However, an inter-ESS with intra-subnet handoff and an intra-ESS with inter-subnet handoff may also be possible. Such mismatching ESS-subnet configurations result in performance degradation. This paper proposes FCS, a Further Check Scheme which detects the change of subnet after an intra-ESS handoff and eliminates unnecessary handoff latency after an inter-ESS handoff. The experimental results show that FCS outperforms the conventional implementation of NetworkManager under Linux in terms of handoff latency.
Fluorescent B-10 embedded nanodiamonds as B-10 delivery agent for boron neutron capture therapy
(2019-06-26)
Lin, Bo-Rong
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Kunuku, Srinivasu
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Chen, Tzung-Yuang
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Chang, Yu-Jen
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Liao, Li-Chuan
Boron neutron capture therapy is a potentially powerful anti-cancer treatment, the success of which depends heavily on the boron delivery agent. Enabling the real-time tracing of delivery agents as they move through the body is crucial to the further development of boron neutron capture therapy. In this study, we fabricate fluorescent B-10 embedded nanodiamonds using physical ion implantation in conjunction with a two-step annealing process. Fluorescent B-10 embedded nanodiamonds perform well in cell viability test. The red fluorescence of the B-10 embedded nanodiamonds allows their use in fluorescence microscopy and in vivo imaging systems, thereby making it possible to conduct tracking in real time. The proposed fluorescent B-10 embedded nanodiamonds, combining optical visibility and B-10 transport capability, might be a promising boron delivery agent suitable for a wide range of biomedical applications.
Fluorescent Fe Embedded Magnetic Nanodiamonds Made by Ion Implantation
(2019-02-04)
Lin, Bo-Rong
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Kunuku, Srinivasu
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Chen, Chien-Hsu
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Chen, Tzung-Yuang
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Hsiao, Tung-Yuan
We demonstrate fluorescent Fe embedded magnetic nanodiamonds by ion implantation and two-step annealing. The diamond characteristics with a highly ordered core and a graphite surface layer are maintained after the implantation process. After the two-step annealing process, a bright red fluorescence associated with nitrogen-vacancy centers is observed. These new fluorescent magnetic nanodiamonds can be used as a dual-function in vivo tracer with both optical visibility and magnetic resonance imaging capabilities. They are potentially useful for the more advanced in vivo biological and medical applications.
Highly efficient drug delivery systems based on functional supramolecular polymers: In vitro evaluation
(2016-03-15)
Cheng, Chih-Chia
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Chang, Feng-Chih
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Kao, Wan-Yi
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Hwang, Shiaw-Min
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Liao, Li-Chuan
The novel concept of modifying and enhancing the properties of existing functional micelles through self-complementary interactions has significant potential. In this study, a practical approach to living polymerization of functionalized thermoresponsive monomers enabled the incorporation of self constituted multiple hydrogen bonded groups into micelles that have potential as supramolecular drug-delivery systems. Phase transitions and morphological studies in aqueous solution showed that the microstructure can be controlled to achieve well-defined vesicle-like micelles with respect to the strength of the hydrogen bond segment. Thus, the resulting micelles have a very low critical micellization concentration and very high loading capacity (16.1%), making the loading process extremely stable and efficient. Incorporation of the anticancer drug doxorubicin (DOX) affected the micellization process in aqueous solution and enabled fine-tuning of drug loading and precise control of drug release rate with excellent sensitivity. Release studies in vitro showed that DOX-loaded micelles exerted dose dependent cytotoxicity against human liver carcinoma (HepG2) cells at the physiological temperature of 37 degrees C. In addition, DOX-loaded micelles were efficiently endocytosed by the cancer cells, which may enable the micelles to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. This newly developed material may provide a potential route towards next-generation drug delivery vehicles. Statement of Significance A breakthrough innovation in water-based thermo-responsive polymers has enabled significant progress in developing smart stimuli-responsive nanocarriers by generating novel "supramolecular polymeric micelles" via self-complementary hydrogen-bonding interactions. These newly developed micelles exhibit extremely high micellar stability and drug loading capacity (up to 16%), excellent thermo-responsive behavior and precise control of drug release rate due to hydrogen-bond-induced physical cross-linking. In addition, doxorubicin-loaded micelles were efficiently endocytosed by the cancer cells, which allows them to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. Thus, this work provides a potential route for the development of next generation multifunctional nanocarriers that have improved safety and to increase the therapeutic efficacy of anticancer therapy. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Iron embedded magnetic nanodiamonds for in vivo MRI contrast enhancement
(2019-12-11)
Lin, Bo-Rong
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Chen, Chien-Hsu
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Chang, Chun-Hsiang
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Kunuku, Srinivasu
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Chen, Tzung-Yuang
Although nanodiamonds have long being considered as a potential tool for biomedical research, the practical in vivo magnetic resonance imaging (MRI) application of nanodiamonds remains relatively unexplored. In this paper, we present the first application of in vivo MRI contrast enhancement using only iron embedded magnetic nanodiamonds. An MR image enhancement was clearly demonstrated in the rendering of T2-weighted images of mice obtained using an unmodified commercial MRI scanner. The excellent contrast obtained using these nanodiamonds opens the door to the non-invasive in vivo tracking of nanodiamonds and image enhancement. In the future, one can apply these magnetic nanodiamonds together with surface modifications to facilitate drug delivery, targeted therapy, localized thermal treatment, and diagnostic imaging.
Isolation of Mesenchymal Stem Cells with Neurogenic Potential from the Mesoderm of the Amniotic Membrane
(2010)
Chang, Yu-Jen
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Hwang, Shiaw-Min
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Tseng, Ching-Ping
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Cheng, Fu-Chou
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Huang, Shih-Hung
The amniotic membrane has been clinically applied as a therapeutic material in wound covering and corneal surface reconstruction. Recently, mesenchymal stem cells (MSCs) have been isolated from the placenta, specifically from the amniotic membrane. However, the localization of MSCs in the amniotic membrane has not been determined. In this study, term placenta was collected, and we performed immunohistochemical staining techniques to identify and localize MSCs in the mesoderm of the amniotic membrane in situ with MSC antibodies, including CD90 and CD105. We further directly cultured and characterized MSCs from the amniotic membrane mesoderm (AMSCs). The AMSCs were easily isolated and represented a homogenous fibroblastic morphology at early passages. In addition to MSC surface markers, AMSCs expressed Sox2, Oct-4 and Nanog. AMSCs could be induced into osteocytes, adipocytes and chondrocytes in vitro and show immunosuppressive effects on T-cell proliferation. Under appropriate conditions, AMSCs could differentiate into neuronal-like cells, which were identified by neuronal-specific markers and their ability to secrete dopamine. This study reveals that AMSCs provide a promising source for stem cell studies and also extend the clinical potential of the amniotic membrane in the field of regenerative medicine. Copyright (C) 2010 S. Karger AG, Basel
NEW HEURISTICS FOR SOLVING THE ECONOMIC LOT SCHEDULING PROBLEM WITH REWORKS
(2011-02-01)
Chang, Yu-Jen
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Yao, Ming-Jong
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運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
In this study, we are interested in the economic lot scheduling problem (ELSP) that considers manufacturing of the serviceable products and remanufacturing of the rework products. In this paper, we formulate a mathematical model for the ELSP with reworks using the common cycle approach in which only one manufacturing lot and only one rework lot for each product exist during a common cycle. In order to solve this problem, we propose two heuristics that not only search for the optimal cycle time and an optimal production sequence, but also utilize a simple scheduling heuristic to schedule the starting time of all the manufacturing and rework lots so as to minimize the average total costs. The first heuristic is a simple heuristic that employs a 2-opt search to obtain a close-to-optimal production sequence. The second heuristic, which is a refined version of the simple heuristic, employs a bisection search to look for an optimal cycle time. In our numerical experiments, we compare the effectiveness of both heuristics using randomly generated instances.
Secondary ion mass spectrometry to verify the implantation of magnetic ions in nanodiamonds
(2019-11-07)
Lin, Bo-Rong
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Wang, Chiung-Chi
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Chen, Chien-Hsu
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Kunuku, Srinivasu
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Hsiao, Tung-Yuan
Ion implantation is used to create nanodiamonds (NDs) with embedded magnetic ions for use in a wide range of biological and medical applications; however, the effectiveness of this process depends heavily on separating magnetic NDs from nonmagnetic ones. In this study, we use secondary ion mass spectrometry to verify the implantation of magnetic ions in NDs and the success of separation. When applied to a series of NDs with embedded iron or manganese ions, the sorting tool used in this study proved highly effective in selecting magnetic NDs. Besides, multienergy ion implantation and precise thickness control of NDs coating on the silicon wafer were suggested to improve this technology. Published under license by AIP Publishing.
Solving the economic lot scheduling problem with multiple facilities in parallel using the time-varying lot sizes approach
(2009)
Yao, Ming-Jong
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Chang, Yu-Jen
;
運輸與物流管理系註：原交通所+運管所
;
Department of Transportation and Logistics Management
The conventional Economic Lot Scheduling Problem (ELSP) is concerned with the lot sizing and scheduling of several products so as to minimize the average total costs on a single facility. This study is interested in an extension of the ELSP, namely, the ELSP with multiple identical facilities in parallel (which is also called the multi-facility ELSP). In order to solve this problem efficiently, we propose two solution approaches in a two-phase scheme in this study. In the first phase, we use an existing heuristic and a genetic algorithm to search for better product assignments that determine which product should be produced on which facility. When an assignment is secured, we employ a Time-Varying Lot Sizes (TVLS) heuristic to obtain a feasible production sequence (or schedule) for each facility in the second phase. Our numerical experiments show that our approaches outperform an existing heuristic in the literature when the problem size is large and the facility utilization rate is high. On the other hand, we have an interesting observation that was never reported in the literature, namely, the TVLS approach may obtain worse solutions than a well-known upper bound in the literature for some cases.