Floor Performance Research Articles

Modern Performance Monitoring

The modern Unix server floor can be a diverse universe of hardware from several vendors and software from several sources. Often, the personnel needed to resolve server floor performance issues are not available or, for security reasons, not allowed to be present at the very moment of occurrence. Even when, as luck might have it, the right personnel are actually present to witness a performance "event," the tools to measure and analyze the performance of the hardware and software have traditionally been sparse and vendor-specific. Because few real Unix cross-platform toolkits exist, there is no standard method for administrators to accurately view an event, record it for later analysis, or share it with additional qualified personnel for an efficient resolution.

Constraining LDPC degree distributions for improved error floor performance

The error floor performance of finite-length irregular low-density parity-check (LDPC) codes can be very poor if code degree distributions are chosen to optimize the threshold performance. In this paper we show that by constraining the optimization process, a balance between threshold and error floor' performance can be obtained. The resulting degree distributions give the best threshold performance subject to some minimum requirement on the error floor

Flexible construction of irregular partitioned permutation LDPC codes with low error floors

Irregular partitioned permutation (IPP) low-density parity-check (LDPC) codes have been recently introduced to facilitate hardware implementation of belief propagation (BP) decoders. In this letter, we present a new method to construct IPP LDPC codes with great flexibility in the selection of code parameters. Meanwhile, small stopping sets are avoided in the code construction, thus good error floor performance can be achieved.

What Top Management Thinks About the Benefits of Hard and Soft Manufacturing Technologies

Each year, billions of dollars are spent by U.S. manufacturers to acquire hard and soft manufacturing technologies. Hard technologies are bundle of equipment, computer hardware and software such as computer numerical control, computer-aided manufacturing, robots, etc. In contrast, soft technologies are manufacturing techniques and know-how such as just-in-time, total quality management, statistical quality control, etc.- hardware is not essential to their successful use but can enhance their scope and effectiveness. This large empirical study of 1042 U.S. manufacturing plants develops a model to study the impact of manufacturing technology use on various performance measures; this study provides first evidence from the field that soft manufacturing technologies have many times the measurable effects of hard technologies on product, process, and business performance. Further, the effects of technology use are enhanced by the skilled use of technology. Implications for research and public policy are addressed. This paper has found that, in the opinion of top management in manufacturing firms, soft technologies have an impact on 1) shop floor performance; 2) product line breadth; and 3) growth and profitability. These finding should make the investment in soft technologies easier to justify. If top management controls the purse, and if it sees a link between investment in soft technology and tangible benefits in these three areas, getting top management to invest in soft technology should be easier. Before deciding on requests for investments in soft technologies, we hope top managers would seriously consider the findings of this paper.

The urine stream interruption test and pelvic muscle function in the puerperium

Objectives: This study assesses the role of the uroflowmetric urine stream interruption test (UST) in the evaluation of postpartum pelvic floor muscle function. Method: Two months after vaginal delivery, 492 women who underwent a digital test, vaginal manometry, and a UST were divided into two groups: continent and incontinent. Variables were subjected to the Student's t-test and to Fisher's exact test to verify the difference between the two groups. Results: Digital test and vaginal manometry results were higher in the continent group, but only the UST showed significantly different values ( P=0.001). All test results of incontinent puerperae who underwent rehabilitation were significantly improved after treatment. Conclusions: UST is low cost, non-invasive, and can give objective information about pelvic floor performance after a vaginal delivery. It can be used for both routine clinical use and an outcome measure for women who undergo rehabilitation treatment.

Shop Performance Implications of Using Cells, Partial Cells, and Remainder Cells*

ABSTRACTThis paper considers the application of cellular manufacturing (CM) to batch production by exploring the shop floor performance trade‐offs associated with shops employing different levels of CM. The literature has alluded to a continuum that exists between the purely departmentalized job shop and the completely cellular shop. However, the vast majority of CM research exists at the extremes of this continuum. Here, we intend to probe performance relationships by comparing shops that exist at different stages of CM adoption. Specifically, we begin with a hypothetical departmentalized shop found in the CM literature, and in a stepwise fashion, form independent cells. At each stage, flow time and tardiness performance is recorded. Modeling results indicate that, depending on shop conditions and managerial objectives, superior shop performance may be recorded by the job shop, the cell shop, or by one of the shops between these extreme points. In fact, under certain conditions, shops that contain partially formed cells perform better than shops that use completely formed cells. Additional results demonstrate that in order to achieve excellent performance, managers investigating specific layouts need to pay especially close attention to changes in machine utilization as machine groups are partitioned into cells.

A two-phased approach to setting due-dates in single machine job shops

This paper explores the characteristics of job flow time distributions resulting from the use of different priority rules via computer simulation and statistical analysis. Statistical analysis of results from phase I experimentation modeling traditional due-date setting practices are used to develop job flow time prediction models. In phase II simulation experiments, the regression models developed in phase I are used to establish due-date allowances to jobs based on their processing times. Forms of the prediction equations reveal the differences in resultant job flow distributions, and explain the underlying nature of interactions between due-date setting methods and shop performance characteristics of dispatching rules as reported in previous studies. Application of the prediction equations in phase II experimentation show the viability of improving shop floor performance without resorting to looser due-dates.

Setting Performance Targents For New Decision Making Units In DEA

This paper examines the problem of setting targets for a new decision making unit so that the efficiency of that DMU relative to existing units will be at or better than some preset floor performance level. While this problem can arise both on the input and output side, the development here pertains only to the case where outputs are given, while target inputs are to be determined. The situation is examined where limits may be imposed on the potential target inputs. The possibility of nondiscretionary factors is also considered

The relationships between cage floor preferences and performance in broiler chickens

Two experiments were conducted with broiler chickens to determine cage floor preferences, the strength of preference for a particular floor type and to evaluate the effect of rearing broilers on the preferred cage floor on productivity. In experiment 1, chicks when offered free access to either wire (WF) or plastic (PF) mesh flooring, preferred the former. However, when the perferred floor type (WF) was illuminated at 800 lux, birds spent longer time on PF. Also provision of incandescent lamps at PF resulted in broilers spending significantly longer period on WF. In experiment 2, while floor type had no effect on growth of female chicks throughout the duration of study, male chicks grown on PF were heavier than their WF counterparts on Days 21, 28, 35 and 42. Neither livability, nor incidence of breast blisters and leg deformities was affected by floor type.

Construction methods for minimizing vibration levels in floors with lumber joists

The National Building Code of Canada 1990 specifies the allowable spans for lumber floor joists that are expected to lead to satisfactory vibrational behaviour. This paper discusses construction methods that improve the floor behaviour once the flooring and joists appropriate to a particular building occupancy have been selected. Laboratory tests on full-size floors demonstrate that adding between-joists bridging and supporting all four floor edges significantly improves the overall vibrational performance of wood floors. Bridging consisting of solid blocking glued to the underside of the flooring and a mild steel strap nailed to the underside of blocking and joists is more effective than several alternative details. Incorporating pads of damping material between flooring and joists, or at bearings, can have a detrimental effect on floor performance. The use of elastomeric adhesive, in lieu of nailed flooring-to-joist connections, does not significantly enhance the mechanical performance of floors with lumber joists. Key words: lumber, vibration, serviceability, floors, design detailing.

Tooling constraints and shop floor scheduling: A simulation study

AbstractResearch into the problems of job shop scheduling has dealt with two of three major categories of shop floor resources: machine capacity and labor. Generally ignored has been the impact of tooling constraints, the third form of shop floor resource, on the scheduling process. The impact of tooling is the focus of this study.Using a simple simulation model of a shop operating under varying levels of tooling availability, it is shown that the level of tooling availability has a significant impact on shop floor performance as measured in terms of mean flow time, mean tardiness, number jobs tardy and number of tool changes. Four different tooling assignment rules are evaluated and their effect on system performance is described.The results indicate that tooling assignment rules should consider both job priorities and tooling availability in order to achieve good shop performance. The paper concludes with general recommendations for the management of shop orders facing limited tooling availability.