Flexible product platforms

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2005.Includes bibliographical references (leaves 155-162).The research contributes to the uncertainty management of engineering systems by proposing and demonstrating a way to implement flexible platform strategy to respond to future uncertainties. In today's competitive market, where market segments are becoming more fragmented, pressure to develop and market diverse sets of products is increasing. To meet such market needs and reduce production cost at the same time, product platform strategy has been implemented in several different industries. Using a core set of common platform elements and variant-specific unique elements, a family of products can be produced to satisfy various market segments. However, the growing cost of platform development and undesired side effects of the strategy (e.g. performance tradeoff, cannibalization) is forcing companies to design their platforms with flexibility, so they can accommodate product variants, differentiate these variants, and be economically flexible to respond to specified future uncertainties. This thesis introduces a design process to architect flexible product platforms. The proposed process is demonstrated in two automotive application case studies.(cont.) In the first case study, a vehicle floor pan is designed to satisfy two different length requirements, while being economically robust to future specification change and component demand. The second case study investigates a vehicle platform, where the flexible body in white (BIW) platform is designed for a family of three vehicle variants through identification of critical elements subset. Results showed that the flexible BIW platform is less profitable than the inflexible BIW platform, but when the degree of future uncertainty increases, the flexible design eventually becomes more profitable. This research provides additional examples that yet again confirms the general proposition "flexibility gains value as the degree of uncertainty increases."by Eun Suk Suh.Ph.D

Correlating Integrative Complexity With System Modularity

Modularity is the degree to which a system is made up of relatively independent but interacting elements. Modularization is not necessarily a means of reducing intrinsic complexity of the system, but it is a means of effectively redistributing the total complexity across the system. High degree of modularization enable reductionist strategies of system development and is an effective mechanism for complexity redistribution that can be better managed by system developers by enabling design encapsulation. In this paper, we introduce a complexity attribution framework to enable consistent complexity accounting and management procedure and show that integrative complexity has a strong inverse relationship with system modularity and its implication on complexity management for engineered system design and development.Korea (South). Ministry of Education, Science and Technology (MEST) (National Research Foundation of Korea. NRF-2016R1D1A1A09916273

Integrative Complexity: An Alternative Measure for System Modularity

Complexity and modularity are important inherent properties of the system. Complexity is the property of the system that has to do with individual system elements and their connective relationship, while modularity is the degree to which a system is made up of relatively independent but interacting elements, with each module typically carrying an isolated set of functionality. Modularization is not necessarily a means of reducing intrinsic complexity of the system but is a mechanism for complexity redistribution that can be better managed by enabling design encapsulation. In this paper, the notion of integrative complexity (IC) is proposed, and the corresponding metric is proposed as an alternative metric for modularity from a complexity management viewpoint. It is also demonstrated using several engineered systems from different application d omains that there is a strong negative correlation between the IC and system modularity. This leads to the conclusion that the IC can be used as an alternative metric for modularity assessment of system architectures.Korea (South). Ministry of Education, Science and Technology (MEST) (National Research Foundation of Korea. Grant NRF2016R1D1A1A09916273

DETC2006-99163 FLEXIBLE PRODUCT PLATFORMS: FRAMEWORK AND CASE STUDY

ABSTRACT Customization and market uncertainty require increased functional and physical bandwidth in product platforms. This paper presents a platform design process in response to such future uncertainty. The process consists of seven iterative steps and is applied to an automotive body-in-white (BIW) where 10 out of 21 components are identified as potential candidates for embedding flexibility. The method shows how to systematically pinpoint and value flexible elements in platforms. This allows increased product family profit despite uncertain variant demand and specification changes. We show how embedding flexibility suppresses change propagation and lowers switch costs, despite an increase of 34% in initial investment for equipment and tooling. Monte Carlo simulation results for 12 future scenarios reveal the value of embedding flexibility

Hysteroscopic Resection of the Vaginal Septum in Uterus Didelphys with Obstructed Hemivagina: A Case Report

Uterus didelphys with obstructed hemivagina and ipsilateral renal agenesis is a rare congenital anomaly. Excision of the obstructed vaginal septum is the treatment of choice for symptom relief and the preservation of reproductive capability. A 14-yr-old girl complained of persistent vaginal spotting following each menstruation. Pelvic magnetic resonance imaging revealed a uterus didelphys with left hematocolpos and ipsilateral renal agenesis. Instead of conventional transvaginal excision of the vaginal septum, we used hysteroscopic excision under transabdominal ultrasonographic guidance to preserve the integrity of the hymen. The postoperative course was uneventful, and clinical symptoms were completely resolved after this intervention. Resectoscopic excision of the vaginal septum was found to be easy, safe, effective, and appropriate for young women as it preserved hymen integrity. We believe that this is the first Korean report on the use of a hysteroscopy for vaginal septum resection in a patient with uterus didelphys with obstructed hemivagina

A Case of Hypertrophic Osteoarthropathy Associated with Epithelioid Hemangioendothelioma

Epithelioid hemangioendothelioma is a rare vascular tumor, which occurs in the lung, liver, bone, and soft tissue. Hypertrophic osteoarthropathy is a syndrome characterized by subperiosteal new bone formation, joint effusion and clubbing, and may be associated with cyanotic heart disease, chronic pulmonary disease, liver disease, and other miscellaneous diseases. The activation of endothelium and platelets has been suggested to be involved in the development of hypertrophic osteoarthropathy. We report a rare case of hypertrophic osteoarthropathy, which developed in association with hepatic epithelioid hemangioendothelioma with pulmonary metastasis. We also discuss the role of vascular endothelial growth factor in its pathogenesis

High dose therapy followed by autologous peripheral blood stem cell transplantation as a first line treatment for multiple myeloma: a Korean Multicenter Study.

We conducted a phase II multicenter trial to estimate the response and survival of patients with newly diagnosed multiple myeloma to high dose melphalan therapy followed by autologous peripheral blood stem cell transplantation. Eligible patients who had undergone induction with vincristine, adriamycin and dexamethasone (VAD) should have adequate cardiac, pulmonary and renal function (creatinine <2 mg/dL). Melphalan at 200 mg/m2 was used as a conditioning regimen. Eighty patients were enrolled from 13 centers. The median age of the patients was 53 yr (range; 20 to 68 yr). The initial stage was IA/IIA/IIB/IIIA/IIIB in 3/8/1/54/14 patients, respectively. Beta2-microglobulin, CRP and LDH were increased in 74, 42 and 34% of the patients examined. Cytogenetic data were available in 30 patients, and 6 patients showed numeric or structural abnormalities. Two therapy-related mortalities occurred from infection. Among the 78 evaluable patients, CR/PR/MR/NC/PD were achieved in 48/26/2/1/1 patients, respectively. After a median follow-up of 30 months, the median overall and event-free survivals were 66 months (95% CI: 20-112) and 24 months (95% CI: 18-29), respectively. This study verifies the efficacy and feasibility of high dose melphalan therapy with autologous stem cell transplantation in newly diagnosed multiple myeloma

High-dose Chemotherapy and Autologous Stem Cell Rescue in Patients with High-risk Stage 3 Neuroblastoma: 10-Year Experience at a Single Center

High-dose chemotherapy and autologous stem cell rescue (HDCT/ASCR) was applied to improve the prognosis of patients with high-risk stage 3 neuroblastoma. From January 1997 to December 2006, 28 patients were newly diagnosed as stage 3 neuroblastoma. Nine of 11 patients with N-myc amplification and 5 of 17 patients without N-myc amplification (poor response in 2 patients, persistent residual tumor in 2 and relapse in 1) underwent single or tandem HDCT/ASCR. Patients without high-risk features received conventional treatment modalities only. While 8 of 9 patients underwent single HDCT/ASCR and the remaining one patient underwent tandem HDCT/ASCR during the early study period, all 5 patients underwent tandem HDCT/ASCR during the late period. Toxicities associated with HDCT/ASCR were tolerable and there was no treatment-related mortality. While the tumor relapsed in two of eight patients in single HDCT/ASCR group, all six patients in tandem HDCT/ASCR group remained relapse free. The 5-yr event-free survival (EFS) from diagnosis, in patients with N-myc amplification, was 71.6±14.0%. In addition, 12 of 14 patients who underwent HDCT/ASCR remained event free resulting in an 85.1±9.7% 5-yr EFS after the first HDCT/ASCR. The present study demonstrates that HDCT/ASCR may improve the survival of patients with high-risk stage 3 neuroblastoma

MSX1 Polymorphism Associated with Risk of Oral Cleft in Korea: Evidence from Case-Parent Trio and Case-Control Studies

Orofacial clefts, including cleft lip with or without palate (CL/P) and cleft palate (CP), are one of the most common congenital malformations in Asian populations, where the rate of incidence is higher than in European or other racial groups. A number of candidate genes have been identified for orofacial clefts, although no single candidate has been consistently identified in all studies. We performed case-parent trio and case-control studies on 6 single nucleotide polymorphisms (SNPs) in the MSX1 gene using a sample of 52 CL/P and CP probands from Korea. In the case-control study, the allele frequencies of 6 MSX1 SNPs were compared between 52 oral cleft cases and 96 unmatched controls. For the case-parent trio study, single-marker and haplotype-based tests of transmission disequilibrium using allelic and genotypic tests revealed significant evidence of linkage in the presence of disequilibrium for 1170 G/A of exon 2. With the GG genotype as a reference group among GG, GA, and AA genotypes at 1170G/A, the disease risk decreased with the presence of the A allele (AA genotype: OR = 0.26, 95% CI = 0.10-0.99). These results are consistent with evidence from other studies in the US and Chile and confirm the importance of the MSX1 genotype in determining the risk of CL/P and CP in Koreans